Magnetsko ponašanje multiferoičnog CuCl4(C2H5NH3)2

master's thesis

• Title (english): Magnetic behaviour of multiferroic CuCl4(C2H5NH3)2
• Author: Matija Kalanj
• Mentor: Damir Pajić (mentor)
• Committee member: Damir Pajić (predsjednik povjerenstva)
• Committee member: Ivan Kupčić (član povjerenstva)
• Committee member: Emil Tafra (član povjerenstva)
• Committee member: Ivo Batistić (član povjerenstva)
• Committee member: Željko Skoko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2017-02-27, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

Multiferoici su materijali u kojima se istovremeno javljaju dvije ili više vrsta uređenja: feromagnetizam, feroelektričnost, feroelastičnost i ferotoroidalnost. U zadnje vrijeme magnetoelektrični multiferoici su privukli dosta pažnje znanstvene zajednice. U ovim materijalima je naročito pogodno ako su magnetizacija i električna polarizacija povezani, što znači da je magnetizaciju moguće mijenjati pomoću električnog polja i obrnuto. Ovo svojstvo multiferoika je bitno zato što u informatičkoj tehnologiji magnetoelektrični materijali mogu naći primjenu u višestanjskim memorijama ili u uređajima koji štede energiju. Postoje razni materijali koji pokazuju ta svojstva, od oksida među kojima su najpoznatiji: BiFeO3, TbMnO3, HoMn2O5, do metaloorganskih spojeva poput: [(CH3)3NH2]Mn(HCOO)3, (C6H5CH2CH2NH3)2CuCl4. U ovom radu istraživana su magnetska svojstva sintetiziranog multiferoičnog metaloorganskog spoja CuCl4(C2H5NH3)2, i to statička pomoću SQUID magnetometra te izmjenična pomoću AC susceptometra. Okarakteriziran je antiferomagnetski fazni prijelaz koji je posljedica antiferomagnetskog djelovanja između susjednih feromagnetsko uređenih slojeva. Isto tako su primijećeni strukturni prijelazi spoja u magnetskim mjerenjima, kod mjerenja magnetizacije primjećeni su skokovi a zatim i razdvajanje krivulja. Na temperaturama strukturnih prijelaza dolazi do reorganizacije organskih lanaca pri čemu električno polje putem polarnosti mijenja strukturu spoja koja pak mijenja magnetizaciju materijala. Ovaj rezultat ukazuje da je magnetoelektrični učinak moguće dobiti indirektno, koristeći strukturne prijelaze spoja.

Abstract (english)

Multiferoics are materials which combine two or more kinds of orderings: ferromagnetism, ferroelectricity, ferroelasticity and ferrotoroidicity. In recent years magnetoelectric multiferoics have cought attention of the scientific community. In these kind of materials is especially good if the magnetisation and electric polarisation are connected, which would mean that we can change magnetisation with electric field and vice-versa. This property of multiferoics is important in hardware industry, magnetoelectric materials can find use in multistate memories or in the devices which would save energy. There are different kinds of multiferoic materials, from oxides: BiFeO3, TbMnO3, HoMn2O5, to metalorganic compounds: [(CH3)3NH2]Mn(HCOO)3, (C6H5CH2CH2NH3)2CuCl4. In this thesis we researched magnetic properties of multiferoic metalorganic compound CuCl4(C2H5NH3)2 with SQUID magnetometer and AC susceptometer. We report measurements and analysis of magnetic phase transition and structural transitions of this compound. Antiferomagnetic phase transition is the consequence of of antiferomagnetic interaction between the neighbouring ferromagnetic ordered planes. We spotted the structural transitions in magnetic measurements which are characterized by jumps and separations of the curves of magnetisation. On the temperatures of the structural transitions organic chains are reorganised by electric field which changes the structure of the compound which then changes the magnetisation of the material. This result implies that magnetoelectric effect can occur indirectly by using the structural transitions of the compund.

• Keywords: multiferoici; feromagnetizam; feroelastičnost; ferotoroidalnost
• Keywords (english): multiferoics; ferromagnetism; ferroelectricity; ferrotoroidicity
• Language: croatian
• URN:NBN: urn:nbn:hr:217:201049
• Study programme: Title: Physics; specializations in: Research; Course: Research; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-06-13 14:59:50