Title Magnetsko ponašanje lančastih i slojevitih hibridnih metoksietilamonijevih halogenokuprata(II) Title (english) Magnetic behaviour of the chain and layered hybrid methoxyethylammonium halocuprates(II) Author Nikola Miše Mentor Damir Pajić (mentor)Committee member Damir Pajić (predsjednik povjerenstva)Committee member Ivan Kupčić (član povjerenstva)Committee member Miroslav Požek (član povjerenstva)Committee member Mihael Srđan Grbić (član povjerenstva)Committee member Mario Novak (član povjerenstva)Granter University of Zagreb Defense date and country 2024-07-12, Croatia Scientific / art field, NATURAL SCIENCES Abstract Sve veći broj istraživanja u posljednje vrijeme ukazuje da hibridni organsko-anorganski halogenometalati omogućuju otkrivanje složenosti nisko-dimenzionalnih magnetskih sustava koji imaju i fundamentalnu i praktičnu vrijednost. Dosad neistraženi spojevi izvedeni iz metoksietilamina i bakrovih(II) halogenida, kristalizirali su ili kao diskretni (mononuklearni) koordinacijski spojevi ili kao hibridni organsko-anorganski sustavi lančaste, odnosno slojevite strukture. U ovom radu istražujemo magnetsko ponašanje nekoliko takvih spojeva u širokom rasponu temperatura i magnetskih polja koristeći SQUID magnetometar. Modeliranjem statičke magnetizacije određujemo jakost magnetskih interakcija i opisujemo dimenzionalnost magnetskog podsustava, čime proširujemo razumijevanje fundamentalnih mehanizama magnetskih fenomena i omogućujemo doprinos razvoju novih materijala i metoda usmjerenih na optimizaciju njihovih svojstava. Mononuklearni spojevi diklorobis(metoksietilamin)bakar(II) i dibromobis( metoksietilamin)bakar(II) ponašaju se kao antiferomagnetski lanci, s maksimumom magnetizacije oko T = 10 K, a medu lancima postoje još slabe sekundarne interakcije. Međutim, uređeno stanje, ispod T = 3 K, opaženo je samo za bromidne uzorke. Spojevi metoksietilamonijeva bromokuprata(II) s geometrijom lanaca imaju maksimum magnetizacije oko T = 90 K, te u sustavu postoje i znatno slabije interakcije među antiferomagnetskim lancima. Ponašanje spojeva metoksietilamonijeva klorokuprata(II) s geometrijom lanaca nalikuje na ponašanje feromagnetskih lanaca smještenih na antiferomagnetsku rešetku pa tako podsjeća i na ponašanje slabog feromagneta. Također, zapažamo magnetsko uređenje ispod temperature TC = 6.4 K, ali i izostanak saturacije čak i u polju H = 7 T. Slično njima, magnetska mjerenja spojeva metoksietilamonijeva tetraklorokuprata(II) slojevite strukture također ukazuju na magnetsko uređenje ispod TC = 6.4 K i antiferomagnetske interakcije među ravninama, ali i relativno meko feromagnetsko ponašanje postižući 80% saturacije magnetizacije u polju od H = 500 Oe. Mjerenjem kristalića istog slojevitog materijala uočene su laka magnetska ravnina i teška magnetska os okomita na klorokupratne ravnine.
Abstract (english) Increasing number of studies in recent times suggest that hybrid organic-inorganic halometallates pave the way for unveiling the intricacies of low-dimensional magnetic systems, which hold both fundamental and applicative value. Novel studied compounds derived from methoxyethylamine and copper(II) halides crystalized either as mononuclear complexes or as hybrid organic-inorganic systems with chain or layered structures. Here, we examine the magnetic behaviour of several such structures over a wide range of temperatures and magnetic fields using the SQUID magnetometer. By modeling static magnetization, we determine the strength of magnetic interactions and describe the dimensionality of the magnetic subsystem, widening the understanding of the fundamental mechanisms of magnetic phenomena and fostering the development of new materials and methods aimed at optimizing their properties. Both dichlorobis( methoxyethylamine)copper(II) and dibromobis(methoxyethylamine)copper(II) mononuclear compounds behave as antiferromagnetic chains, with broad maximum of magnetization around T = 10 K, with weak inter-chain coupling. However, an ordered state was observed only for the latter compound, below T = 3 K. Methoxyethylammonium bromocuprate(II) compounds with chain geometry display broad maximum of magnetization around T = 90 K, and significantly weaker inter-chain interactions were observed in this system. Methoxyethylammonium chlorocuprate(II) compounds with chain geometry behave as ferromagnetic chains superimposed on an antiferromagnetic lattice, resembling the behaviour of a soft ferromagnet, with an observed ordered state below TC = 6.4 K, but no saturation even at field H = 7 T. Similarly, methoxyethylammonium tetrachlorocuprate(II) compounds with layered structure display an ordered state below TC = 6.4 K and antiferromagnetic interactions between planes but a relatively soft ferromagnetic behaviour with 80% saturation magnetization at field H = 500 Oe. Measuring plate-like crystals of this layered material, an easy magnetic plane and a hard magnetic axis perpendicular to the chlorocuprate planes were observed.
Keywords
metaloorganski spojevi
halogenokuprati
niskodimenzionalni sustavi
magnetometrija
mononuklearni spojevi
spinski lanci
spinske ravnine
superizmjena
magnetska uredenja
magnetska anizotropija
Keywords (english)
metal-organic compounds
halocuprates
low-dimensional systems
magnetometry
mononuclear compounds
spin chains
spin sheets
superexchange
magnetic ordering
magnetic anisotropy
Language croatian URN:NBN urn:nbn:hr:217:165606 Study programme Title: The University Integrated Undergraduate and Graduate Programme in Physics; Research Physics; specializations in: Research Physics Type of resource Text File origin Born digital Access conditions Open access Terms of use Public note Ovaj rad nastao je u okviru projekta HRZZ IP-2024-10-6321. Created on 2024-07-26 10:51:07
