Ferromagnetism in Co7(TeO3)4Br6: A byproduct of complex antiferromagnetic order and single-ion anisotropy

Znanstveni rad - Izvorni znanstveni rad

• Autor: Mladen Prester
• Autor: Ivica Živković
• Autor: O. Zaharko
• Autor: Damir Pajić
• Autor: P. Tregenna-Piggott
• Autor: Helmut Berger
• Autorova ustanova: Sveučilište u Zagrebu; Prirodoslovno-matematički fakultet; (Fizički odsjek)
• Znanstveno / umjetničko područje, polje i grana: PRIRODNE ZNANOSTI; Fizika

Sažetak (engleski)

Pronounced anisotropy of magnetic properties and complex magnetic order of a new oxi-halide compound Co7(TeO3)4Br6 has been investigated by powder and single-crystal neutron-diffraction, magnetization, and ac susceptibility techniques. Anisotropy of susceptibility extends far into the paramagnetic temperature range. A principal source of anisotropy are anisotropic properties of the involved octahedrally coordinated single Co2+ ions, as confirmed by angular-overlap-model calculations presented in this work. Incommensurate antiferromagnetic order sets in at TN=34 K. The propagation vector is strongly temperature dependent reaching k1=(0.9458(6) ,0,0.6026(5)) at 30 K. A transition to a ferrimagnetic structure with k2=0 takes place at TC=27 K. The magnetically ordered phase is characterized by very unusual anisotropy as well: while M-H scans along the b axis reveal spectacularly rectangular but otherwise standard ferromagnetic hysteresis loops, M-H studies along other two principal axes are perfectly reversible, revealing very sharp spin-flop (or spin-flip) transitions, such as in a standard antiferromagnet (or metamagnet). Altogether, the observed magnetic phenomenology is interpreted as an evidence of competing magnetic interactions permeating the system, in particular of the single-ion anisotropy energy and the exchange interactions. Different coordinations of the Co2+ ions involved in the low-symmetry C2/c structure of Co7(TeO3)4Br6 render the exchange-interaction network very complex by itself. Temperature-dependent changes in the magnetic structure, together with an abrupt emergence of a ferromagnetic component, are ascribed to continual spin reorientations described by a multicomponent, but yet unknown, spin Hamiltonian.

• Ključne riječi (engleski): magnetic order; magnetic interactions
• Jezik: engleski
• Vrsta publikacije: Znanstveni rad - Izvorni znanstveni rad
• Status objave: Objavljen
• Vrsta recenzije: Recenziran - međunarodna recenzija
• Verzija publikacije: Objavljena verzija rada (izdavačev PDF)
• Naslov časopisa: Physical review B: Condensed matter and materials physics
• Brojčani podaci: vol. 79, br. 14, 144433
• p-ISSN: 1098-0121
• e-ISSN: 1550-235X
• DOI: https://doi.org/10.1103/PhysRevB.79.144433
• URN:NBN: urn:nbn:hr:217:879982
• Datum objave publikacije: 2009
• Projekt: Šifra: 035-0352843-2845; Naziv (hrvatski): Kvantni magneti: Osnovna stanja u kompeticiji; Voditelj: Mladen Prester; Pravna nadležnost: Hrvatska; Financijer: MZOS; Linija financiranja: ZP
• Projekt: Šifra: 119-1191458-1017; Naziv (hrvatski): Nanomagneti; Voditelj: Krešo Zadro; Pravna nadležnost: Hrvatska; Financijer: MZOS; Linija financiranja: ZP
• URL dokumenta: http://link.aps.org/doi/10.1103/PhysRevB.79.144433
• Vrsta resursa: Tekst
• Prava pristupa: Otvoreni pristup
• Javna napomena: Copyright (2009) by the American Physical Society. Received 2 February 2009; revised manuscript received 4 April 2009; published 29 April 2009.
• Datum i vrijeme pohrane: 2019-10-20 17:53:04