NMR Investigations on the Spin Fluctuations in Itinerant Antiferromagnets III. CrB₂

Abstract

The properties of the spin fluctuations in the typical d-band metal CrB₂ have been studied in both the paramagnetic and the ordered states by using the pulsed NMR technique. The temperature dependences of the staggered moment M_Q and the nuclear spin-lattice relaxation rate 1⁄T₁ of ¹¹B above T_N are found to be explained neither from the spin fluctuation theory of weakly antiferromagnetic limit nor from the local moment limit, indicating that CrB₂ is an intermediate substance in the magnetic point of view. It could be pointed out however that the observed Curie-Weiss behavior of the uniform susceptibility χ_u(T) with a large negative Weiss constant (θ_p\simeq−900 K) is a manifestation of the case where the amplitude of the spin density fluctuations is relatively large, corresponding to strong electron-electron interactions and is in general accord with the recent unified theory of magnetism in narrow band electron systems.