Plonųjų manganitų sluoksnių tyrimas stipriuose impulsiniuose elektriniuose ir magnetiniuose laukuose ; Investigation of thin manganite films at strong pulsed electric and magnetic fields

Sujets

• Magnétorésistance
• Manganite
• Physics

Informations

• Publié par: vilnius_gediminas_technical_university
• Publié le: 01 janvier 2006
• Nombre de lectures: 79
• Poids de l'ouvrage: 2 Mo

Extrait

VILNIUS GEDIMINAS TECHNICAL
UNIVERSITY
SEMICONDUCTOR PHYSICS
INSTITUTE
Piotras Cimmperman
INVESTIGATION OF THIN MANGANITE
FILMS AT STRONG PULSED ELECTRIC
AND MAGNETIC FIELDS
Doctoral Dissertation
Physical Sciences, Physics (02P),
Condensed Matter (P260)
Vilnius, 2006VILNIUS GEDIMINAS TECHNICAL UNIVERSITY
SEMICONDUCTOR PHYSICS INSTITUTE
Piotras Cimmperman
INVESTIGATION OF THIN MANGANITE FILMS
AT STRONG PULSED ELECTRIC AND MAGNETIC
FIELDS
Doctoral Dissertation
Physical Sciences, Physics (02P),
Condensed Matter (P260)
Vilnius, 2006Doctoral dissertation was prepared at the Semiconductor Physics Institute
(Vilnius, Lithuania) in 2001–2005
Scientific Supervisor
˙Dr Nerija ŽURAUSKIENE (Semiconductor Physics Institute, Physical
Sciences, Physics – 02P)
Consultant
Dr Habil Saulius BALEVIČIUS (Semiconductor Physics Institute, Physical
Sciences, Physics – 02P)VILNIAUSGEDIMINOTECHNIKOSUNIVERSITETAS
PUSLAIDININKIŲFIZIKOSINSTITUTAS
PiotrasCimmperman
PLONŲJŲMANGANITŲSLUOKSNIŲTYRIMAS
STIPRIUOSEIMPULSINIUOSEELEKTRINIUOSEIR
MAGNETINIUOSELAUKUOSE
Daktarodisertacija
Fiziniaimokslai,fizika(02P),
kondensuotosmedžiagos(P260)
Vilnius,2006Disertacija rengta 2001–2005 metais Puslaidininkiu˛ fizikos institute.
Moksline˙ vadove˙
˙dr. Nerija ŽURAUSKIENE (Puslaidininkiu˛ fizikos institutas, fiziniai mokslai,
fizika – 02P).
Konsultantas
habil. dr. Saulius BALEVIČIUS (Puslaidininkiu˛ fizikos institutas, fiziniai
mokslai, fizika – 02P).Acknowledgments
De˙koju Didele˙s galios impulsu˛ laboratorijai, suteikusiai galimybę man pa-
ruošti ši˛ darbą. Ypatingai de˙kingas darbo vadovei dr. Nerijai Žurauskienei už
visokeriopą pagalbą, mokslines diskusijas ir vertingus patarimus. Taip pat esu
labai de˙kingas habil. dr. Sauliui Balevičiui už vertingas ide˙jas ir pasiulytus
iškilusiu˛ moksliniu˛ klausimu˛ sprendimo kelius, dr. Voitechui Stankevič už vi-
sokeriopą pagalbą, atliekant eksperimentus ir interpretuojant gautus rezul-
tatus, geru˛ ominiu˛ kontaktu˛ užgarinimą bei pagalbą, analizuojant sluoksniu˛
strukturą.
Esu de˙kingas dr. Fiodorui Anisimovui ir dr. Valentinai Plaušinaitienei už
manganitu˛ sluoksniu˛ gamybą, habil. dr. Evaldui Tornau ir Vytautui Petraus-
kui už pagalbą, skaičiuojant sluoksniu˛ magnetines savybes, dr. Jurijui No-
vickij, pade˙jusiam pritaikyti stipriu˛ magnetiniu˛ lauku˛ generatoriu˛ manganitu˛
sluoksniu˛ tyrimams, dr. Olegui Kiprianovič, supažindinusiam su nanosekun-
dine˙s trukme˙s elektriniu˛ impulsu˛ tyrimo metodika, dr. Jonui Paršeliunui už
visokeriopą techninę pagalbą, dr. Renatai Butkutei už visokeriopą pagalbą tiek
Puslaidininkiu˛fizikosinstituteVilniuje,tiekirorganizuojantmatavimusVaršu-
vos fizikos institute, Linai Belkevičienei už disertacijos santraukos redagavimą.
De˙koju Kristinai, Skirmantui, Julijai, Irmantui už gerai praleistą laiką ins-
titute ir diskusijas.
Atskirai noriu pade˙koti mylimiems: mamai, žmonai Danguolei ir sunui
Mantui už meilę, rupesti˛, supratingumą ir kantrybę.
I would like to thank Prof Dr Habil Jacek Kossut for organized measure-
ments of magnetic properties of manganite films at the Institute of Physics
PAS (Warsaw, Poland). I am thankful to Dr Maciej Sawicki and Dr Marta
Aleszkiewicz for performed measurements of magnetization of the films.Contents
Preface i
1 Literature review 1
1.1 Basic phenomenology of manganites . . . . . . . . . . . . . . . . 1
1.2 Electrical transport properties . . . . . . . . . . . . . . . . . . . 4
1.2.1 Low field conductivity . . . . . . . . . . . . . . . . . . . 4
1.2.2 Strong field conductivity . . . . . . . . . . . . . . . . . . 10
1.3 Magnetoresistance . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.3.1 Low field magnetoresistance . . . . . . . . . . . . . . . . 15
1.3.2 High field magnetoresistance . . . . . . . . . . . . . . . . 16
2 Preparation of the samples 19
2.1 MOCVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2 PLD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3 Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3 Measurement equipment and used methods 22
3.1 Pulsed electric field . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2 Pulsed magnetic field . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 Other characterization methods . . . . . . . . . . . . . . . . . . 25
4 Sample characterization 27
4.1 Strain induced by substrates . . . . . . . . . . . . . . . . . . . . 27
4.2 Microstructure . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2.1 Films on NGO, STO and LAO substrates . . . . . . . . 29
4.2.2 Films on lucalox, sapphire and MgO substrates . . . . . 31
4.3 Surface morphology . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.3.1 LCMO films . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.3.2 LSMO films . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.4 Temperature dependence of low resistivity of manganite epitax-
ial films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.4.1 Strain effect . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.4.2 Resistance dependence on film thickness . . . . . . . . . 374.4.3 Simulation of epitaxial film T . . . . . . . . . . . . . . . 41C
4.5 Temperaturedependenceoflowfieldresistivityofpolycrystalline
films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5 Electroresistance 48
5.1 Epitaxial films . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2 Polycrystalline films . . . . . . . . . . . . . . . . . . . . . . . . 52
5.2.1 La Ca MnO films . . . . . . . . . . . . . . . . . . . 520.67 0.33 3
5.2.2 La Sr MnO films . . . . . . . . . . . . . . . . . . . 540.83 0.17 3
5.2.3 Analysis of GB transport . . . . . . . . . . . . . . . . . . 55
5.3 Hybrid superconductor-magnetic fault current limiter . . . . . . 59
6 Magnetoresistance 63
6.1 MR of epitaxial films . . . . . . . . . . . . . . . . . . . . . . . . 63
6.2 MR of polycrystalline films . . . . . . . . . . . . . . . . . . . . 68
6.3 Strong magnetic field sensor . . . . . . . . . . . . . . . . . . . . 73
Summary and main conclusions 81
References 83
List of publications 96
Abbreviations 98
Abstract (in Lithuanian) 100Preface
Motivation and aim of the dissertation
Achievements in modern electronics over the past few decades have re-
sulted in the development of new devices which operation is based on physical
phenomena in magnetic oxides. Manganite oxides (manganites), especially of
composition La A MnO with A = Ca, Sr, Ba, exhibiting colossal magne-1−x x 3
toresistance (CMR) phenomenon were intensively studied both experimentally
and theoretically in order to clear up their physical properties important for
potential applications. As a result, spintronic devices, such as non-volatile
magnetic random access memories (MRAM), spin valve and read heads are
already in use in industry. Despite of the wide application of manganites de-
vices operating at low magnetic fields, there are some other important areas of
powerful electric motors, magnetic levitating trains, magnetic flux compression
generators, electromagnetic launchers or metal forming systems, which require
sensing of much larger magnetic fields. It was demonstrated that CMR phe-
nomenon could be used for these purposes [1, 2]. However, sensor used for
measurements of short strong magnetic field pulses (with amplitudes up to 20–
50 Tesla and duration in microseconds and milliseconds range) has to satisfy
several important requirements: it has to be of low dimensions (active area
2less than 50×50 m ), response signal to magnetic field has to be linear as
possible and without saturation at high fields, sensor has to show high-speed
responsiveness and sensitivity independence to the direction of the magnetic
field. Therefore, it is important to investigate physical phenomena which are
responsible for MR peculiarities in thin films of manganite oxides, especially
focusing on MR sensitivity, anisotropy, and “hysteresis” effects. It has been
observed that manganites exhibiting colossal magnetoresistance phenomenon
are also sensitive to electric fields that induce strong decreases in the electrical
resistance of these materials. This effect was named electroresistance (ER)
and was suggested to use in the development of fast fault current limiters to
protect high-speed electronic devices against short electromagnetic pulses [3].
However, the origin of ER is still unclear and seems different in bulk ceramics,
single crystals, and thin films of manganites. This makes difficult the further
application of the ER phenomenon. Therefore, it is very important to investi-
i