Temperature Susceptibility and Magnetization Near TN

A paramagnetic molar susceptibility Xmoi = 0-38 cm /mol is derived from the NMR spectrum at 4 K for a compositionally unspecified TmSe sample by Jones [1]. Fig. 176 shows the temperature dependence of Xmoi up to 20K for samples with a = 5.622 to 5.707 A. The susceptibilities of a nearly stoichiometric sample above 50 K at ambient pressure and at 

3 kbar are exactly the same, but at T, the ratio between Xmoi at ambient pressure and at 

Temperature dependence of the reciprocal magnetic susceptibility 1/Xmoi for Tm Se samples with lattice constants from a = 5.622 to 5.707 A (Fig. 176, for clearness the curves are shifted by 5 K) and for nearly stoichiometric TmSe at ambient pressure and at 8.3 kbar up to room temperature (Fig. 177). 

Magnetization curves for nearly stoichiometric TmSe at 1.4 K as a function of field strength and applied pressures are shown in Fig. 180a to c, p. 354. The extrapolated value where the step disappears is about 20 kbar for all three orientations and it was concluded that transitions III and IV disappear. The temperature of the maximum in the low field magnetization at - 3 K (boundary I) increases with increasing pressures (—0.1 K/kbar) and the maximum flattens for the [111] direction and fields up to 7.3 kbar, Missell etal. [4, pp. 280/1]. For the pressure dependence of a at fields along [100] and 1.4 K, also see Guertin et al. [3]. 

A saturation moment of 1.87(10) iq perTm ion is derived from neutron diffraction studies at Tn (3.30 K) on a nearly stoichiometric polycrystalline sample with a = 5.705 A (at room temperature), Debray et al. [16]. An ordered antiferromagnetic moment of h=1.7 0.2 b per Tm ion is derived for nearly stoichiometric TmSe with a = 5.71 A (at room temperature) by Shapiro et al. [17] from neutron diffraction studies. A sample with the same lattice constant has n= 1.9, 2.3, and 2.2 per Tm ion at 4.2 Kand pressures of 0,8, and 20 kbar, respectively, Vettieret al. [18]. The pressure dependence of x at T is shown in Fig. 181 for TmSe (with a = 5.709 A at room temperature). A maximum of 2.20(10) b is indicated at 16.5 kbar. Debray etal. [19]. 

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