Structure, magnetic and thermodynamic properties of heterometallic ludwigites: Cu2GaBO5 and Cu2AlBO5

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:515

Article

Eremina, R. M.¹  Gavrilova, T. P.¹  Moshkina, E. M.²  Gilmutdinov, I. F.³  Batulin, R. G.³  Gurzhiy, V. V.⁴  Grinenko, V.^5,6  Inosov, D. S.⁶ 

[1] RAS, FRC Kazan Sci Ctr, Zavoisky Phys Tech Inst, Sibirsky Tract 10-7, Kazan 420029, Russia

[2] RAS, Kirensky Inst Phys, Fed Res Ctr, KSC,SB, Krasnoyarsk 660036, Russia

[3] Kazan Fed Univ, Inst Phys, Kazan 420008, Russia

[4] St Petersburg State Univ, Dept Crystallog, Inst Earth Sci, Univ Emb 7-9, St Petersburg 199034, Russia

[5] IFW Dresden, Leibniz Inst Solid State & Mat Res, D-01069 Dresden, Germany

[6] Tech Univ Dresden, Inst Solid State & Mat Phys, D-01069 Dresden, Germany

关键词: Crystal structure;    Ludwigite;    Quasi-one-dimensional magnetism;    Antiferromagnetic order;    Specific heat;    Magnetization;   

DOI  :  10.1016/j.jmmm.2020.167262

来源: Elsevier

【 摘 要 】

We present an extensive study of the structural, magnetic and thermodynamic properties of high-quality monocrystals of two heterometallic oxyborates from the ludwigite family: Cu2GaBO5 and Cu2AlBO5 in the temperature range above 2 K. The distinctive feature of the investigated structures is the selective distribution of Cu and Ga/Al cations. The unit cell of Cu2GaBO5 and Cu2AlBO5 contains four nonequivalent crystallographic sites of metal ions. Two sites in the structure of Cu2GaBO5 are fully occupied by Cu atoms which form the quasi one-dimensional chains along the a-axis. For Cu2AlBO5 all sites are partially occupied by Al and Cu atoms. The joint analysis of low-temperature data on magnetic susceptibility and magnetic contribution to the specific heat showed that Cu2AlBO5 and Cu2GaBO5 exhibit an antiferromagnetic transition at T-N = 2.4 and 4.1 K, respectively. The magnetic response below T-N can be represented as the sum of two contributions: the ordered component and the paramagnetic contribution from defects of the same relative weight. It is shown that the external magnetic field above 2.5T and 2.8T for Cu2GaBO5 and Cu2AlBO5, respectively, leads to a broadening of the magnetic phase transition indicating suppression of the long-range antiferromagnetic order.

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