Investigation of the functional Investigation of the functional

properties of ferroelectric/properties of ferroelectric/multiferroicmultiferroicproperties of ferroelectric/properties of ferroelectric/multiferroicmultiferroic

systemssystems

CS. CS. Dr. Dr. Felicia GHEORGHIUFelicia GHEORGHIU

E-mail: felicia.gheorghiu@uaic.ro

Outlook

2. Electrical characterisation of BiFeO 3-based multiferroicsystems by impedance spectroscopy (IS)

1. Introduction

systems by impedance spectroscopy (IS)�Precision LCR Meter�Impedance/Gain-Phase Analyzer

3. Preparation of BiFeO 3 multiferroic micro/nanostructures �Hydrothermal synthesis

4. PZT –based multiferroic thin films�RF magnetron Sputtering

5. Fabrication of PPLN samples � e-field poling method

�

PhD degree in Physics in 2012 with thesis title “Study of the electrical and magnetic properties of single phase and composite multiferroic systems”,Supervisor Prof.Dr.Liliana Mitoseriu

IntroductionIntroduction

� Magnetoelectrics multiferroics =Co-existance of both ferro/ferri/antiferroelectric and ferro/ferri/antif erromagnetic order in a certain range of temperatures and coupling between them (ME effect).

Magnetoelectric Multiferroics: →→→→ trends in the microelectronic industry:

Applications:

� Miniaturized components with multifunctional properties

Why multiferroic materials?Why multiferroic materials?

Applications:

� Multiple state memory elements (writing/reading/deleting with E, H fields and opti cally)

� ME sensors, transducers, etc.

� SpintronicsRequirement:

� ME materials must exhibit high ME coefficients at r oom temperature

� C. Binek, B. Doudin, “Magnetoelectronics with

magnetoelectrics”, J. Phys.: Condens. Matter 17, L39–L44 (2005)

1. Electrical characterisation of BiFeO 3-based multiferroic system by impedance spectroscopy (IS)� Precision LCR Meter

� Impedance/Gain-Phase Analyzer

Agilent E4980A Precision LCR Meter controlled via L AN Agilent E4980A Precision LCR Meter controlled via L AN with a computerwith a computer (from AMON(from AMON--CARPHAT Platform)CARPHAT Platform)

Direct measured: R,X,CDirect measured: R,X,CDirect measured: R,X,CDirect measured: R,X,CCalculated: Calculated: Calculated: Calculated: εεεε’, tg’, tg’, tg’, tgδδδδ, , , , εεεε’’, M’,M’’, ’’, M’,M’’, ’’, M’,M’’, ’’, M’,M’’, σσσσ

Frequency: 20Hz Frequency: 20Hz Frequency: 20Hz Frequency: 20Hz –––– 2MHz2MHz2MHz2MHz

SolartronSolartron Impedance/GainImpedance/Gain--Phase Analyzer model Phase Analyzer model 1260A from the “1260A from the “Dielectrics,FerroelectricsDielectrics,Ferroelectrics and and MultiferroicsMultiferroics” Laboratory of the “” Laboratory of the “AlexandruAlexandru IoanIoanCuzaCuza” University” University

� Precision LCR Meter

Direct measured: Direct measured: Direct measured: Direct measured: νννν, , , , εεεε’,’,’,’,εεεε’’, ’’, ’’, ’’, σσσσ, , , , R,X,R,X,R,X,R,X,Calculated: M’,M’’, tgCalculated: M’,M’’, tgCalculated: M’,M’’, tgCalculated: M’,M’’, tgδδδδ

Frequency: 1Hz Frequency: 1Hz Frequency: 1Hz Frequency: 1Hz –––– 1MHz1MHz1MHz1MHz

Sample typeSample typeSample typeSample type

�The electrical measurements were performed The electrical measurements were performed The electrical measurements were performed The electrical measurements were performed on parallelon parallelon parallelon parallel----plate capacitor configuration, by plate capacitor configuration, by plate capacitor configuration, by plate capacitor configuration, by applying Ag electrodes onto the polished surfaces applying Ag electrodes onto the polished surfaces applying Ag electrodes onto the polished surfaces applying Ag electrodes onto the polished surfaces

� Precision LCR Meter

Direct measured: R,X,C,Direct measured: R,X,C,Direct measured: R,X,C,Direct measured: R,X,C, LLLLCalculated: Calculated: Calculated: Calculated: εεεε’, tg’, tg’, tg’, tgδδδδ, , , , εεεε’’, M’,M’’, ’’, M’,M’’, ’’, M’,M’’, ’’, M’,M’’, σσσσ,,,,ρρρρ

Frequency: 20Hz Frequency: 20Hz Frequency: 20Hz Frequency: 20Hz –––– 20MHz20MHz20MHz20MHz

Wayne Kerr 6500P LCR Meter Wayne Kerr 6500P LCR Meter from the RAMTECH from the RAMTECH Centre of the “Centre of the “AlexandruAlexandru IoanIoan CuzaCuza” University” University

applying Ag electrodes onto the polished surfaces applying Ag electrodes onto the polished surfaces applying Ag electrodes onto the polished surfaces applying Ag electrodes onto the polished surfaces of the sintered ceramic disks with diameters in of the sintered ceramic disks with diameters in of the sintered ceramic disks with diameters in of the sintered ceramic disks with diameters in the range of 9the range of 9the range of 9the range of 9----10 mm and 110 mm and 110 mm and 110 mm and 1---- 2 mm thickness.2 mm thickness.2 mm thickness.2 mm thickness.

Investigated Investigated multiferroicmultiferroic systemssystems

�BiFeO3 based single-phase multiferroic systems

Pure BiFeO3ceramics

(1-x)BiFeO 3-xBaTiO 3

BiFe1-xMnxO3

ceramics

BiFeO3-based solid solution

Unsolved problems:Unsolved problems:Unsolved problems:Unsolved problems:

�To explain the macroscopic properties in relation with microstructure and composition of the singleTo explain the macroscopic properties in relation with microstructure and composition of the singleTo explain the macroscopic properties in relation with microstructure and composition of the singleTo explain the macroscopic properties in relation with microstructure and composition of the single----phase BiFeOphase BiFeOphase BiFeOphase BiFeO3333 compoundscompoundscompoundscompounds�To understand the mechanisms of conduction and dielectric relaxationTo understand the mechanisms of conduction and dielectric relaxationTo understand the mechanisms of conduction and dielectric relaxationTo understand the mechanisms of conduction and dielectric relaxation

Bi 1-yLayFe1-xMnxO3

Conductivity anomalyConductivity anomaly

10-3

10-1

101

103

BiFeO3 T=204 K

T=224 K

T=244 K

T=264 K

T=303 K

T=343 K

T=383 K

T=423 K

T=124 K

T=143 K

T=164 K

T=184 K

Re

( εε εε )

(x10

6 )

1E-13

1E-11

1E-9

1E-7

1E-5

1E-3 BiFeO3

Con

duct

ivity

σ σ σ σ

(S/m

)

T=303 K

T=343 K

T=383 K

T=423 K

T=204 K

T=224 K

T=244 K

T=264 K

T=124 K

T=143 K

T=164 K�a a a a strong reduction strong reduction strong reduction strong reduction with frequency of the with frequency of the with frequency of the with frequency of the εεεε

100 101 102 103 104 105 10610-5

Frequency (Hz)

100 101 102 103 104 105 1061E-15

Frequency (Hz)

Con

duct

ivity

T=264 K T=164 K

T=184 K with frequency of the with frequency of the with frequency of the with frequency of the εεεε

� two region two region two region two region in in in in conductivity plot :conductivity plot :conductivity plot :conductivity plot :1) almost constant1) almost constant1) almost constant1) almost constant2) a large increase,2) a large increase,2) a large increase,2) a large increase,

separated by the range separated by the range separated by the range separated by the range of temperature of temperature of temperature of temperature (189 (189 (189 (189 –––– 244) K 244) K 244) K 244) K

-16

-12

-8

-4

0

BiFeO3

E1=0.86 eV

E2=1.5 eV

undetermined

T1=189 K

Log

( σσ σσdc

in S

/m)

1E-7

1E-6

1E-5

1E-4

1E-3

0,01

0,1

II

f=1Hz f=10Hz f=100Hz f=1kHz f=2kHz f=10kHzσσ σσ'

x 1

0-2(S

/m)

I

11.. FeliciaFelicia GheorghiuGheorghiu,, MihaiMihai Calugaru,Calugaru, AdelinaAdelina Ianculescu,Ianculescu, ValentinaValentina MusteataMusteata andand LilianaLiliana MitoseriuMitoseriu,, PreparationPreparation andand functionalfunctionalcharacterizationcharacterization ofof BiFeOBiFeO 33 ceramicsceramics:: aa comparativecomparative studystudy ofof thethe dielectricdielectric propertiesproperties ,, SolidSolid StateState Sciences,Sciences, SolidSolid StateState SciencesSciences2323 ((20132013)) 7979--878722.. LaviniaLavinia CurecheriuCurecheriu,, FeliciaFelicia GheorghiuGheorghiu , AdelinaAdelina IanculescuIanculescu,, LilianaLiliana MitoseriuMitoseriu,, NonNon--linearlinear dielectricdielectric propertiesproperties ofof BiFeOBiFeO 33ceramics,ceramics, ApplAppl.. PhysPhys.. LettLett.. 9999,, ((20112011)) 17290417290433. . Felicia GheorghiuFelicia Gheorghiu , Lavinia Curecheriu, Adelina Ianculescu, Mihai Calug aru and Liliana MitoseriuLavinia Curecheriu, Adelina Ianculescu, Mihai Calug aru and Liliana Mitoseriu, Tunable dielectric , Tunable dielectric characteristics of characteristics of MnMn--doped BiFeO3 doped BiFeO3 multiferroicmultiferroic ceramics, ceramics, ScriptaScripta MaterialiaMaterialia 68 (2013) 30568 (2013) 305––308308

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5

-20T2=244 KL

og

103/T (K -1)100 150 200 250 300 350 400 450

1E-9

1E-8

1E-7 f=10kHz f=20kHz f=100kHz f=200kHz f=1MHz

Temperature (K)

Dielectric characteristicsDielectric characteristics

210

220

230

240

250R

eal p

art o

f per

mitt

ivity

x=0

x=0.25

(1-x)BiFeO3-xBaTiO

3

x=0.15

0,010

0,015

0,020

0,025

0,030

0,035

(1-x)BiFeO3-xBaTiO

3

Tan

gent

loss

tan

δδ δδ

x=0 x=0,05 x=0,1 x=0,15 x=0,25 x=0,3

104 105 106

180

190

200

Rea

l par

t of p

erm

ittiv

ity

x=0.1

x=0.05x=0.3

Frequency (Hz)

104 105 1060,000

0,005

0,010

Frequency (Hz)

Tan

gent

loss

tan

⇒⇒⇒⇒ Presence of BaTiOPresence of BaTiOPresence of BaTiOPresence of BaTiO3333 in solid solution results in: in solid solution results in: in solid solution results in: in solid solution results in: ---- elimination of conduction mechanisms ,elimination of conduction mechanisms ,elimination of conduction mechanisms ,elimination of conduction mechanisms ,---- stabilization stabilization stabilization stabilization εεεε’=(180’=(180’=(180’=(180----240) and 240) and 240) and 240) and

x=0

1. 1. Felicia Felicia PrihorPrihor ,, AdelinaAdelina IanculescIanculescuu,, LilianaLiliana Mitoseriu, Mitoseriu, PetronelPetronel Postolache, Postolache, LaviniaLavinia Curecheriu, Dragan N. Curecheriu, Dragan N. aand Crisan D., nd Crisan D., Functional properties of the (1Functional properties of the (1--x)BiFeOx)BiFeO 3 3 –– xBaTiOxBaTiO 33 solid solutions, solid solutions, Ferroelectrics 391 (2009) 76 Ferroelectrics 391 (2009) 76 –– 82 82 2. 2. Felicia Felicia PrihorPrihor GheorghiuGheorghiu , AdelinaAdelina IanculescuIanculescu, , PetronelPetronel PostolachePostolache, , NicoletaNicoleta LupuLupu, Marius , Marius DobromirDobromir, , DumitruDumitru Luca, Luca, LilianaLilianaMitoseriuMitoseriu, Preparation and properties of (1, Preparation and properties of (1--x)BiFeOx)BiFeO 33 –– xBaTiOxBaTiO 33 multiferroicmultiferroic ceramics, J. Alloys Compd. 506 (2010) 862ceramics, J. Alloys Compd. 506 (2010) 862––867 867 3. 3. Adelina Ianculescu, Adelina Ianculescu, Felicia Prihor GheorghiuFelicia Prihor Gheorghiu , Petronel Postolache, Ovidiu Oprea, Liliana Mitose riu, Petronel Postolache, Ovidiu Oprea, Liliana Mitose riu, The role of doping on the , The role of doping on the structural and functional properties of BiFestructural and functional properties of BiFe 1−x1−xMnMn xxOO33 magnetoelectricmagnetoelectric ceramics, J. Alloys Compd. 504(2010) 420ceramics, J. Alloys Compd. 504(2010) 420––426426

---- stabilization stabilization stabilization stabilization εεεε’=(180’=(180’=(180’=(180----240) and 240) and 240) and 240) and ---- reduction of dielectric losses below 3% at room reduction of dielectric losses below 3% at room reduction of dielectric losses below 3% at room reduction of dielectric losses below 3% at room temperature.temperature.temperature.temperature.

2. Preparation of BiFeO 3 micro/nanostructures�Hydrothermal synthesis

Advantages:Advantages:Advantages:Advantages:� low low low low temperatures temperatures temperatures temperatures ((((< 200< 200< 200< 200°°°°C);C);C);C);� reaction takes place in a closed system under reaction takes place in a closed system under reaction takes place in a closed system under reaction takes place in a closed system under a high pressure a high pressure a high pressure a high pressure as an additional parameter as an additional parameter as an additional parameter as an additional parameter (besides temperature, precursors, solution pH, reaction time)(besides temperature, precursors, solution pH, reaction time)(besides temperature, precursors, solution pH, reaction time)(besides temperature, precursors, solution pH, reaction time)

Univ. of Genoa & Institute of Univ. of Genoa & Institute of Univ. of Genoa & Institute of Univ. of Genoa & Institute of Univ. of Genoa & Institute of Univ. of Genoa & Institute of Univ. of Genoa & Institute of Univ. of Genoa & Institute of EnergeticsEnergeticsEnergeticsEnergeticsEnergeticsEnergeticsEnergeticsEnergetics and and and and and and and and InterphasesInterphasesInterphasesInterphasesInterphasesInterphasesInterphasesInterphasesIENIIENIIENIIENIIENIIENIIENIIENI--------CNR, GenoaCNR, GenoaCNR, GenoaCNR, GenoaCNR, GenoaCNR, GenoaCNR, GenoaCNR, Genoa, Italia, Italia, Italia, Italia, Italia, Italia, Italia, Italia

The hydrothermal treatments The hydrothermal treatments The hydrothermal treatments The hydrothermal treatments The hydrothermal treatments The hydrothermal treatments The hydrothermal treatments The hydrothermal treatments were conducted in the were conducted in the were conducted in the were conducted in the

temperature range 180temperature range 180temperature range 180temperature range 180----220220220220°°°°C C C C for 4for 4for 4for 4----48h.48h.48h.48h.

The reaction furnace and The reaction furnace and The reaction furnace and The reaction furnace and hydrothermal vesselhydrothermal vesselhydrothermal vesselhydrothermal vessel

200°C/48h 220°C/48h BiFeOBiFeO33 powderspowders

MicrostructuralMicrostructural characterizationcharacterization

180°C/48h

Felicia Felicia GheorghiuGheorghiu , , RaduRadu TanasaTanasa, Maria Teresa , Maria Teresa BuscagliaBuscaglia, , VincenzoVincenzo BuscagliaBuscaglia, , Cristina G. Cristina G. PastravanuPastravanu, , EvelineEveline PopoviciPopovici and and LilianaLiliana MitoseriuMitoseriu, Preparation of , Preparation of BiBi 22FeFe44OO99 particles by hydrothermal synthesis and functional properties,particles by hydrothermal synthesis and functional properties, Phase Phase Transit 86 (7) (2013) 726Transit 86 (7) (2013) 726--736736

180°C/4h 180°C/8h

Optimum conditions: Optimum conditions: Optimum conditions: Optimum conditions: -180180180180°°°°C C C C reaction temperature, reaction temperature, reaction temperature, reaction temperature, - 8h8h8h8h reaction time, reaction time, reaction time, reaction time, - 0.0016670.0016670.0016670.001667 mol/L precursors mol/L precursors mol/L precursors mol/L precursors concentration, concentration, concentration, concentration, - 1.2 mol/L 1.2 mol/L 1.2 mol/L 1.2 mol/L NaOH NaOH NaOH NaOH concentration.concentration.concentration.concentration.

RAMTECH Centre: RAMTECH Centre: powders and ceramic preparation

Analytical Balance Analytical Balance Analytical Balance Analytical Balance GHGHGHGH----252252252252----ECECECEC

Ball Milling Ball Milling Ball Milling Ball Milling GrindingGrindingGrindingGrinding

Hydraulic PressHydraulic PressHydraulic PressHydraulic Press----CarverCarverCarverCarver

Auto Precision Auto Precision Auto Precision Auto Precision PolishingPolishingPolishingPolishing MachineMachineMachineMachine

Carbolite FurnaceCarbolite FurnaceCarbolite FurnaceCarbolite Furnace

Complex impedance Complex impedance Complex impedance Complex impedance investigationinvestigationinvestigationinvestigation

3. PZT –based multiferroic thin films�RF magnetron Sputtering

Substrate positioningSubstrate positioningSubstrate positioningSubstrate positioning

1

43

2

electrical Top electrode

Substrate positioningSubstrate positioningSubstrate positioningSubstrate positioningThe target after deposition The target after deposition The target after deposition The target after deposition

(broken)(broken)(broken)(broken)

Sample preparation for electrical measurements:

Deposition conditions:Deposition conditions:Ceramic target : Co-doped Pb(Zr 0.54Ti0.46)O3

(Kurt J. Lesker Company)Diameter: 3.00"Substrate: Au/Al 2O3Discharge in ArBasic pressure: 2 ××××10-6 mbarWorking pressure: 1.5 ××××10-3 mbarSubstrate temperature: 300°C

Schematic representation of a Schematic representation of a Schematic representation of a Schematic representation of a sputtering systemsputtering systemsputtering systemsputtering system

PZT AuBottom electrodeAl2O3

electrical contacts

Top electrode

as-deposited films

CoCo--doped PZT thin films doped PZT thin films

characterizationcharacterization

1. 1. RalucaRaluca FrunzaFrunza, Dan , Dan RicinschiRicinschi, , Felicia GheorghiuFelicia Gheorghiu , , RaduRadu ApetreiApetrei, , DumitruDumitru Luca, Luca, LilianaLiliana MitoseriuMitoseriu, Masanori , Masanori OkuyamaOkuyama , , Preparation and Preparation and characterisationcharacterisation of PZT films by RFof PZT films by RF--magnetron sputtering magnetron sputtering , , J. Alloys Compd. 509 (201 1) 6242J. Alloys Compd. 509 (2011) 6242––6246 6246 2. 2. Felicia Felicia GheorghiuGheorghiu , RaduRadu ApetreiApetrei, Marius , Marius DobromirDobromir, , AdelinaAdelina IanculescuIanculescu, , DumitruDumitru Luca, Luca, LilianaLiliana MitoseriuMitoseriu, Investigation of Co, Investigation of Co--doped PZT films deposited by doped PZT films deposited by rfrf--magnetron sputte ring, Processing and Application of Ceramics 8[3] (2014) 113magnetron sputtering, Processing and Application o f Ceramics 8[3] (2014) 113--120120

Advantages of RF Sputtering: Advantages of RF Sputtering: Advantages of RF Sputtering: Advantages of RF Sputtering: Advantages of RF Sputtering: Advantages of RF Sputtering: Advantages of RF Sputtering: Advantages of RF Sputtering: 1. It works well with insulating targets 1. It works well with insulating targets 1. It works well with insulating targets 1. It works well with insulating targets 2. High efficiency: easier to keep plasma going 2. High efficiency: easier to keep plasma going 2. High efficiency: easier to keep plasma going 2. High efficiency: easier to keep plasma going which can operate at lower which can operate at lower which can operate at lower which can operate at lower ArArArAr pressures (1pressures (1pressures (1pressures (1----15 15 15 15 mTorrmTorrmTorrmTorr))))

RAMTECH Centre RAMTECH Centre ––thin films depositionthin films deposition

Pulsed Laser Deposition (PLD) Pulsed Laser Deposition (PLD) Pulsed Laser Deposition (PLD) Pulsed Laser Deposition (PLD) systemsystemsystemsystem

Magnetron sputtering system type Magnetron sputtering system type Magnetron sputtering system type Magnetron sputtering system type Q150T S/E/ESQ150T S/E/ESQ150T S/E/ESQ150T S/E/ES

PrinciplePrinciplePrinciplePrinciplePrinciplePrinciplePrinciplePrinciple

Substrate Substrate Substrate Substrate holderholderholderholder

Pulsed laser Pulsed laser Pulsed laser Pulsed laser sourcesourcesourcesource

holderholderholderholder

To vacuum To vacuum To vacuum To vacuum pumppumppumppump

Rotating Rotating Rotating Rotating target stagetarget stagetarget stagetarget stage

4. Fabrication of PPLN samples � e-field poling method

EEEE----field poling setupfield poling setupfield poling setupfield poling setup

PPLN=Periodically Poled LiNbO

Substrate after Substrate after Substrate after Substrate after Single domain Single domain Single domain Single domain

Photoresist maskPhotoresist maskPhotoresist maskPhotoresist mask

E-field poling method steps:

PPLN=Periodically Poled LiNbO 3

Substrate after Substrate after Substrate after Substrate after removing the removing the removing the removing the external electric external electric external electric external electric fieldfieldfieldfield

Single domain Single domain Single domain Single domain ferroelectric substrateferroelectric substrateferroelectric substrateferroelectric substrate Inversion of ferroelectrics Inversion of ferroelectrics Inversion of ferroelectrics Inversion of ferroelectrics

domains by application of domains by application of domains by application of domains by application of an electric fieldan electric fieldan electric fieldan electric field

RAMTECH Project PN-II-ID-JRP-2014:

“INtegrated Quantum Circuits based on non-linear waveguide Arrays”

Parteners:

Research Center on Advanced Materials and Technologies (RAMTECH) Sciences Department, "Alexandru Ioan Cuza” University of Iaşi,

Laboratoire de Physique de la Matière Condensée (LPMC), Université de Nice – Sophia Antipolis, Nice, France

Laboratoire de Photonique et Nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Paris, France

ConclusionsConclusions

� Electrical characterisation of ceramics by impedance spectroscopy (IS)

BiFe Mn O

30 60BiFe Mn O

2 3 4 5 60

10

20

30 BiFe1-xMnxO3

Re

ε∗

ε∗

ε∗

ε∗ (

x100

0)

Log of frequency (Hz)

x=0 x=0.10 x=0.20 x=0.30 x=0.40

2 3 4 5 60

5

10

15

20

25 BiFe1-xMnxO3

Log of frequency (Hz)

Tan

δδ δδ

x=0 x=0.10 x=0.20 x=0.30 x=0.40

0 2 4 6 8 100

10

20

30

40

50BiFe1-xMnxO3

Re ε∗ ε∗ ε∗ ε∗ (x1000)

Im ε

∗

ε∗

ε∗

ε∗ (

x100

0)

x=0 x=0.10 x=0.20 x=0.30 x=0.40

� Fabrication of PPLN samples by e-field poling method

Inversion of ferroelectrics Inversion of ferroelectrics Inversion of ferroelectrics Inversion of ferroelectrics domains by application of domains by application of domains by application of domains by application of an electric fieldan electric fieldan electric fieldan electric field

Thank you for your attention!