Magnetic susceptibility and magnetization of the ionic ferromagnets dipotassium, dirubidium, and dicaesium tetrachlorochromate(II)

摘要: High-temperature (300–80 K) susceptibility data are reported for polycrystalline samples of the ionic ferromagnets M2CrCl4(M = K, Rb, or Cs) and interpreted using high-temperature series-expansion method quadratic-layer Heisenberg S= 2 ferromagnet to yield estimates 7·0, 8·5, 6·5 cm–1 nearest-neighbour exchange integrals. Low-temperature (80–4·2 magnetization measurements also Rb2CrCl4 Cs2CrCl4. In both compounds obeys equation {1 –[M(T)/M(0)]}=CTγ with γ= 1·54 up 60 i.e. ca 0·9 Tc. Saturation magnetizations 0·4 B.M. lower than expected ions.