Crystal structures and magnetic properties of lanthanide containing borates LnM(BO3)2 (Ln=Y, Ho–Lu; M=Sc, Cr)

Abstract

The synthesis, crystal structures and magnetic properties of LnM(BO 3 ) 2 (Ln = Y, Ho-Lu; M = Sc, Cr) were investigated. The LnCr(BO 3 ) 2 compounds crystallize in the dolomite-type structure with space group R 3 , in which the Ln and Cr ions occupy two octahedral sites. From the result of structural analysis, it was found that there is an anti-site disorder between these two sites and its chemical formula is more exactly Ln 1-r Cr r [Cr 1-r Ln r ](BO 3 ) 2 . On the other hand, the LnSc(BO 3 ) 2 adopt the calcite-type structure with space group R 3 c. The Ln and Sc ions randomly occupy an octahedral site and the chemical formula is represented as (Ln 0.5 Sc 0.5 )BO 3 . From the magnetic susceptibility and specific heat measurements, we found that all the LnCr(BO 3 ) 2 show an antiferromagnetic transition at 6.1-8.1 K. This transition is mainly due to the ordering of Cr 3+ magnetic moments. Among the compounds with magnetic Ln 3+ ions, only YbCr(BO 3 ) 2 shows an antiferromagnetic ordering of Ln 3+ ion at 2.1 K.-3 -

Magnetic ground states and magnetodielectric effect inRCr(BO3)2(R=Yand Ho)

“…2(c)). Currently, it seems that this decreased magnetic moment is likely affected by the R/Cr anti-site disorder which has been characterized by Doi et al 52 We estimate the anti-site disorder in our sample to be ∼3% from our elastic neutron scattering Rietveld refinements (as discussed below). There is also a notable slope change in the magnetization data measured at 2 K around H = 2.5 T. Moreover, Fig.…”

“…2(b) the temperature dependence of the dc magnetic susceptibility measured between H = 0.1 and 3.0 T for HoCr(BO 3 ) 2 also shows an AFM transition at T N = 9 K which decreases with applied field and vanishes at H = 3.0 T. The Curie-Weiss analysis of the 1/χ data above 100 K resulted in an effective magnetic moment of µ ef f = 10.99 µ B and a Curie temperature of θ CW = -15.1 K which are again in good agreement with the previously reported values. 52 The dc magnetization measured at 2 K shown in Fig. 2(d) saturates around 9 µ B , and there is a slope change which appears around H = 2.0 T. The field dependence of the ac susceptibility measured at 0.3 K shown in Fig.…”

“…The studies of HoCr(BO 3 ) 2 have shown that it crystallizes in the rhombohedral space group R3 and has a dolomite-type structure with a small amount of anti-site disorder between the Ho and Cr sites. 52 As shown in Fig. 1(a), both the Ho and Cr ions occupy octahedral sites which form a three dimensional network by sharing corner-oxygen ions.…”

Crystal structures and magnetic properties of iron borates containing lanthanides Sr6LnFe(BO3)6 (Ln = La, Pr, Nd, Sm Lu)

“…For example, the family of LnM 3 (BO 3 ) 4 borates have been extensively studied because they show interesting optical properties [1,2], structural and magnetic phase transitions [3], and multiferroic behavior [4]. In addition, the dolomite-type borates LnM(BO 3 ) 2 (Ln ¼ Y, HoeLu; M ¼ Cr) having an alternating connecting structure of LnO 6 and CrO 6 octahedra show an antiferromagnetic behavior at low temperatures [5].…”

Cation effect investigation on electronic structure, magnetic and optical properties of Li2Pb2CuB4O10

“…Pb 2 Cu 3 B 4 O 11 shows a spin-gap behavior that can be explained by a spin model of Cu-Cu dimers. Moreover, typical examples to investigate magnetic transition can be found in LnM(BO 3 ) 2 (Ln = Y, Ho-Lu; M = Sc, Cr) systems, all the LnCr(BO 3 ) 2 show transition phenomena due to the long-range magnetic ordering of Cr 3+ magnetic moments, while YbCr(BO 3 ) 2 shows a two-step antiferromagnetic ordering due to Cr 3+ and Yb 3+ magnetic ions [13].…”