Magnetic ordering in Sc sub(2)CoSi sub(2)-type R sub(2)FeSi sub(2) (R=Gd, Tb) and R sub(2)CoSi sub(2) (R=Y, Gd-Er) compounds

• Published in: Journal of magnetism and magnetic materials 2016-09, Vol.413, p.97-107
• Main Authors: Morozkina, A V, Knotkoa, A V, Yapaskurtb, VO, Panic, M, Nirmalae, R, Quezadof, S, Malikf, S K
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Entropy; Ferromagnetism; Magnetic properties; Magnetic transitions; Magnetism; Magnetization; Rare earth metals
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2016.04.034

Magnetic and magnetocaloric properties of Sc sub(2)CoSi sub(2)-type R sub(2)TSi sub(2) (R=Gd-Er, T=Fe, Co) compounds have been studied using magnetization data. These indicate the presence of mixed ferromagnetic and antiferromagnetic interactions in these compounds. One observes a ferromagnetic transition followed by an antiferromagnetic order and a further possible spin-reorientation transition at low temperatures. Compared to Gd sub(2){Fe, Co}Si sub(2), the Tb sub(2)FeSi sub(2) and {Tb-Er} sub(2)CoSi sub(2) compounds exhibit remarkable hysteresis (for e.g. Tb sub(2)FeSi sub(2) shows residual magnetization M sub(res)/Tb=2.45 mu sub(B), coercive field H sub(coer)=14.9 kOe, and critical field H sub(crit)~5 kOe at 5 K) possibly due to the magnetocrystalline anisotropy of the rare earth. The R sub(2){Fe, Co}Si sub(2) show relatively small magnetocaloric effect (i.e. isothermal magnetic entropy change, Delta S sub(m)) around the magnetic transition temperature: the maximal value of MCE is demonstrated by Ho sub(2)CoSi sub(2) ( Delta S sub(m)=-8.1 J/kg K at 72 K and Delta S sub(m)=-9.4 J/kg K at 23 K in field change of 50 kOe) and Er sub(2)CoSi sub(2) ( Delta S sub(m)=-13.6 J/kg K at 32 K and Delta S sub(m)=-8.4 J/kg K at 12 K in field change of 50 kOe).