Istraživanje magnetskog ponašanja metalo-organskih slojevitih perovskita bakra(II) pomoću SQUID-magnetometra

master's thesis

• Title (english): Investigation of magnetic behaviour of the copper(II) metal-organic layered perovskites using SQUID magnetometer
• Author: Karolina Bakić
• Mentor: Damir Pajić (mentor)
• Committee member: Damir Pajić (predsjednik povjerenstva)
• Committee member: Mario Basletić (član povjerenstva)
• Committee member: Katarina Jeličić (član povjerenstva)
• Committee member: Maja Planinić (član povjerenstva)
• Committee member: Nikola Poljak (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2022-03-11, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

Posljednjih su godina zbog svojih fizičkih svojstava metalo-organski slojeviti perovskiti postali predmetom mnogih znanstvenih istraživanja. Metalo-organski spojevi triflouretilamonijeva tetrabromokuprata (F_3EA)_2CuBr_4 i triflouretilamonijeva tetraklorkuprata (F_3EA)_2CuCl_4 pripadaju obitelji slojevitih perovskitnih materijala koji potencijalno mogu pokazati multiferoičnost. Sastoje se od feromagnetskih oktaedarskih slojeva između kojih se nalazi dvosloj organskih kationa. U ovom istraživanju proučavali smo magnetsko ponašanje navedenih spoja pomoću SQUID magnetometra namijenjenoga za proučavanje magnetskih svojstava sitnih eksperimentalnih uzoraka kroz široki raspon temperatura i magnetskih polja. Izmjerene su temperaturne ovisnosti magnetizacije M(T) za tri različite vrijednosti vanjskog primijenjenog polja i izotermne ovisnosti magnetizacije o polju M(H) pri temperaturama od 2 K i 20 K. Temperaturne ovisnosti magnetizacije za (F_3E_A)2CuBr_4 pokazale su postojanje feromagnetskog faznog prijelaza na Curieovoj temperaturi T_C = 12.8 K, dok su temperaturne ovisnosti magnetizacije za spoj (F_3EA)_2CuCl_4 pokazale postojanje karakterističnog antiferomagnetskog faznog prijelaza pri T_N = 8.9 K koji je posljedica antiferomagnetskih interakcija između susjednih feromagnetsko uređenih slojeva. Izotermna mjerenja ovisnosti magnetizacije prikazana su magnetskim histerezama koje su pokazale feromagnetsko ponašanje na temperaturama manjim od temperatura faznog prijelaza. Time su okarakterizirana osnovna magnetska svojstva ovih novih spojeva.

Abstract (english)

In the last decade, due to their physical properties, metal-organic layered pervoskites became a subject of many scientific investigations. Metal-organic compounds such as triflourethylammonium tetrabromocuprate (F_3EA)_2CuBr_4 and triflourethylammonium tetrachlorocuprate (F_3EA)_2CuCl_4 belong to a family of layered pervoskite materials that could be potentially multiferroic. They are composed of ferromagnetic octahedric layers, interbedded with double layer of organic cations. In this research, we studied magnetic behaviour of both aforementioned compounds using the SQUID magnetometer. This device is used for observing magnetic properties in small experimental samples through a wide range of temperatures and magnetic fields. We measured temperature dependence of magnetisation M(T) in three different applied external magnetic fields and isothermal field dependence of magnetisation at temperatures 2 K and 20 K. Temperature dependence of magnetisation for (F_3EA)_2CuBr_4 showed existence of ferromagnetic phase transition at Curie temperature of T_C = 12.8 K, while temperature dependence of magnetisation for compound (F_3EA)_2CuCl_4 showed existence of characteristic antiferromagnetic phase transition at T_N = 8.9 K which is a consequence of antiferromagnetic interactions between neighbouring ferromagnetic layers. Measurements of isothermal field dependence of magnetisation are shown through magnetic hysteresis which exhibit ferromagnetic behaviour at temperatures below the phase transition temperature. By doing so, the basic magnetic properties of these novel compounds are characterized.

• Keywords: metalo-organski spoj; slojeviti perovskiti; magnetizacija; feromagnet; antiferomagnet; susceptibilnost; magnetske histereze; SQUID magnetometar
• Keywords (english): metal-organic compound; layered perovskites; magnetisation; ferromagnet; antiferromagnet; susceptibility; magnetic hysteresis; SQUID magnetometer
• Language: croatian
• URN:NBN: urn:nbn:hr:217:757788
• Study programme: Title: Physics; specializations in: Education; Course: Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije fizike (magistar/magistra edukacije fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-03-11
• Created on: 2022-03-18 15:17:11