Magnetic ordering in Ho(CF3SO3)3⋅9H2O and Ho(C2H5SO4)3⋅9H2O

Abstract

The magnetic susceptibilities χ∥ and χ⊥, both ac (80 Hz) and static, of hexagonal crystals of the structurally similar Ho(C2H5SO4)3⋅9H2O, HoES, and Ho(CF3SO3)3⋅9H2O, HoTFMS, have been measured down to ∼0.1 K. Both order ferromagnetically along the c axis at Tc=0.23 K. Analysis of the susceptibilities above Tc shows g∥≊15.5 and g⊥≊0, ground doublet-excited singlet separation 8.4 K in HoES and 15 K in HoTFMS, and dipolar interionic interactions. Cp for both salts was also measured and found to exhibit similar sharp cooperative λ peaks at 0.23 K due to ordering of the Ho3+ moments. This peak sits atop the rounded Schottky anomaly of a system of nuclear spins in a fixed hyperfine field. The independence of the electron and nuclear contributions to Cp is associated with the Ising character of the Ho3+ ground non-Kramers doublet.

Investigation of magnetic, thermal and hyperfine properties of Tb3+ in the single crystal of terbium trifluoromethanesulfonate nonahydrate

“…4). But, as stated earlier, TbTFMS belongs to the class of materials where ordering of induced magnetic moments in singlet ground-state system takes place; the ferromagnetic transition in this case is reported at 240 mK [3]. Thus, the spins are already aligned along the c-axis in the range of temperature where the anomalies in C N arise; C N should, therefore, be indistinguishable for the two cases, viz., in the presence and absence of an external magnetic field.…”

“…Thus, the spins are already aligned along the c-axis in the range of temperature where the anomalies in C N arise; C N should, therefore, be indistinguishable for the two cases, viz., in the presence and absence of an external magnetic field. But again in this case, substantial ordering of nuclear spins is indicated [3] rendering computation of C N based on disordered phase of nuclear spins invalid.…”

“…The magnetic ordering [2,3], electron paramagnetic resonance (EPR) [4] and heat capacity [3] of a number of RTFMS have been studied by the Friedberg group. They have measured the magnetic properties of TbTFMS in the temperature range 0.05-20 K [2].…”

“…Ordering of magnetic moments, spectra, and magnetic and thermal properties of a relatively new series of compounds, the rare-earth trifluoromethanesulfonate nonahydrates R(CF 3 SO 3 ) 3 Á 9H 2 O or RTFMS where R stands for a trivalent rare-earth ion have been studied extensively [1][2][3][4][5].…”

Magnetic measurements and crystal field investigation on single crystals of Er(CF3SO3)3·9H2O

“…Single crystals of rare earth tri-fluoromethanesulfonate R(CF 3 SO 3 ) 3 Á 9H 2 O [RTFMS, R stands for rare earth] are important materials for their interesting structural, optical, magnetic, thermal and hyperfine properties [1][2][3][4][5][6][7][8][9]. The crystal structures of RTFMS are similar with those of hexagonal hydrated rare earth ethyl-sulfates (RES).…”