Magnetsko ponašanje slojevitih halogenokuprata temeljenih na alifatskim triaminima

master's thesis

• Title (english): Magnetic behaviour of layered halocuprates based on aliphatic triamines
• Author: Petar Havaić
• Mentor: Damir Pajić (mentor)
• Committee member: Damir Pajić (predsjednik povjerenstva)
• Committee member: Damjan Pelc (član povjerenstva)
• Committee member: Ivan Kupčić (član povjerenstva)
• Committee member: Miroslav Požek (član povjerenstva)
• Committee member: Ivan Kokanović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2023-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

Fizička svojstva metalo-organskih spojeva godinama su u fokusu mnogih znanstvenih istraživanja. Halogeno-kuprati temeljenim na alifatskim triaminima su spojevi koji pripadaju skupini slojevitih perovskitnih materijala. Mjereni su spojevi tetraklorokuprata i tetrabromokuprata povezani s alifatskim triaminima koji mogu biti multiferoični. Ta četiri uzorka su: N2N3NCuCl5 i N2N2NCuCl5 te N2N3NCuBr5 i N2N2NCuBr5 (gdje 2 znači dvočlani ugljikov lanac, 3 za tročlani ugljikov lanac, dok N označuje amonijevu skupinu). U mag. sloju su halidnim mostovima spojeni ioni bakra, a među tim vezama nalaze se organski kationi, koji se vežu na njih te međusobno povezuju ravnine čineći cijelu kristalnu stukturu. Ti spojevi su dobri kandidati za pokazivanje multiferoičkog uređenja, jer imaju zanimljiva različita magnetska i električna svojstva. Ovdje smo proučavali magnetska svojstva koristeći SQUID magnetometar za istraživanje magnetskog ponašanja sitnih uzoraka u širem rasponu temperatura i magnetskih polja. Izmjerene su ovisnosti magnetizacija M(T) za nekoliko primjenjenih mag. polja te izotermne ovisnosti o mag. polju M(H), pri temperaturama od 2-50 K. Temperaturne ovisnosti magnetizacija za N2N2NCuBr5 pokazale su postojanje feromagnetskog faznog prijelaza na Curievoj temperaturi 20.5 K, dok su ostali spojevi pokazali antiferomagnetski fazni prijelaz na više različitih temperatura, nižih od spomenutog slabog feromagneta. Uzrok antiferomagnetskih uređenja je slaba interakcija susjednih feromagnetski uređenih slojeva kristalne strukture. Za te spojeve je primjećeno da se na većim jakostima polja (1000 Oe) uspostavlja feromagnetsko ponašanje.

Abstract (english)

Physical properties of the metal-organic compounds have been for years been in focus of exstensive research for many years. Halo-cuprates based on the aliphatic triamines are compounds which belong to group of the layered pervoskite materials, which could be multiferroic. Measured compounds are the tetrachlorocuprates and tetrabromocuprates coupled with aliphatic triamines. These four samples are: N2N3NCuCl5, N2N2NCuCl5 and N2N3NCuBr5, N2N2NCuBr5 (Where 2 means 2 carbon chains, 3 means 3 carbon chains while N means amin group). In magnetic layer halid bridges are bonded with copper ions and between these bonds there are organic cations which bond on to them thus connencting planes which makes the whole crystal structure. Those compounds are good candidates for showing multiferroic ordering, because they have different magnetic and electric properties. Here we were investigating magnetic properties using SQUID magnetometer which is used for purpose of researching the magnetic behaviour of the small samples in a wide range of temperature and magnetic fields. Temperature dependencies of magnetisations M(T) in several magnetic fields and isothermal magnetic hysteresis M(H) at temperatures 2-50 K were measured. Temperature dependencies of magnetisation for N2N2NCuBr5 showed the existence of the ferromagnetic phase transition at Curie temperature of 20.5 K, while other compunds showed the antiferomagnetic phase transitions at different temperatures, lower than before mentioned weak ferromagnet. Cause of the antiferromagnetic ordering is weak interaction between neighbouring ferromagnetic ordered layers of crystal structure. For this compounds it has been noticed that at higher fields (1000 Oe) ferromagnetic behaviour apears.

• Keywords: metalo-organski spoj; slojeviti perovskiti; magnetizacija; feromagneti; antiferomagneti; susceptibilnost; magnetska histereza; SQUID magnetometar; Curieva temperatura; međudjelovanja
• Keywords (english): metal-organic compound; layered perovskites; magnetization; ferromagnet; antiferromagnet; susceptibility; magnetic hysteresis; SQUID magnetometer; Curie temperature; interactions
• Language: croatian
• URN:NBN: urn:nbn:hr:217:669495
• Study programme: Title: The University Integrated Undergraduate and Graduate Programme in Physics and Technology Education; specializations in: Physics and technics; Course: Physics and technics; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: sveučilišni magistar edukacije fizike i tehnike (sveučilišni magistar edukacije fizike i tehnike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-09-27
• Created on: 2024-02-05 14:06:16