The effect of non-magnetic dilution of the Tb sublattice in TbCo₃B₂

Abstract

Solid solutions of Tb(1-x)Y(x)Co(3)B(2) (x=0.05, 0.1, 0.25, 0.4 and 0.5) were studied by neutron powder diffraction, x-ray diffraction, AC susceptibility and SQUID magnetization measurements. Their magnetic and crystallographic properties were deduced and examined together with those previously published for the end compounds (x=0, 1). These solid solutions have hexagonal symmetry and are paramagnetic at RT, and undergo a magnetic ordering transition of the Co sublattice, with the magnetic moments along the hexagonal axis, at T(Co)∼150(15) K, independent of Y concentration. A second magnetic ordering transition of the Tb sublattice T(Tb)≤30 K accompanied by the rotation of the magnetic moments towards the basal plane, was observed for solid solutions with Y concentration x≤0.25. This transition was also found to be accompanied by a crystallographic symmetry decrease. Unexpectedly, neutron powder diffraction showed that the magnitude of the ordered magnetic moment of the Tb ion decreases with Tb concentration.

Large magnetocaloric effect in TbCo3B2 compound

“…The temperature dependence of zero field specific heat results for TbCo 3 B 2 is shown in Fig. 2, a clear -shape indicating a magnetic transition around 28 K which is a typical character of second order phase transition, and no obvious change can be observed around 170 K. These behaviours were consistent with the magnetic measurements and previous reported results [14,15].…”

“…The RCo 3 B 2 compounds are paramagnetic at room temperature and undergo a Co-Co sublattice magnetic order transition at ∼160 (20) K. In addition, a second R-R sublattice magnetic order transition was also observed at 54, 47, 28 and 22 K for R = Gd, Sm, Tb and Dy, respectively [12][13][14][15]. Very recently, a giant/large reversible MCE in ternary R-Co-B intermetallic compounds RCo 2 B 2 (R = Gd, Pr and Nd) [16][17][18] was reported, respectively.…”

“…The ternary intermetallic compounds of the RCo 3 B 2 where R is a rare earth or yttrium have attracted some attentions due to their interesting physical properties [12][13][14][15]. The RCo 3 B 2 compounds are paramagnetic at room temperature and undergo a Co-Co sublattice magnetic order transition at ∼160 (20) K. In addition, a second R-R sublattice magnetic order transition was also observed at 54, 47, 28 and 22 K for R = Gd, Sm, Tb and Dy, respectively [12][13][14][15].…”

Magnetic properties and magnetocaloric effect in GdCo3B2 compound

“…The RCo 3 B 2 compounds are paramagnetic at room temperature and undergo a Co-Co sublattice magnetic order transition at ∼160 (20) K. In addition, a second R-R sublattice magnetic order transition was also observed at 54, 47, 28 and 22 K for R = Gd, Sm, Tb and Dy, respectively [12][13][14][15][16][17][18][19]. Among all the rare-earth transition metal compounds, Gd-based systems [20][21][22] have been extensively investigated owning to that Gd ion has the largest spinorial moment and has the highest effective exchange coupling around room temperature.…”

“…The ternary intermetallic compounds of the RCo 3 B 2 where R is a rare earth or yttrium have attracted some attentions due to their interesting physical properties [12][13][14][15][16][17][18][19]. The RCo 3 B 2 compounds are paramagnetic at room temperature and undergo a Co-Co sublattice magnetic order transition at ∼160 (20) K. In addition, a second R-R sublattice magnetic order transition was also observed at 54, 47, 28 and 22 K for R = Gd, Sm, Tb and Dy, respectively [12][13][14][15][16][17][18][19].…”