Antiferromagnetic phase transition and spin correlations in NiO

作者：Chatterji Tapan^*; McIntyre G J; Lindgard P A

来源：Physical Review B, 2009, 79(17): 172403.

DOI：10.1103/PhysRevB.79.172403

• antiferromagnetic materials
• critical exponents
• frustration
• high-temperature effects
• magnetic transitions
• Neel temperature
• neutron diffraction
• nickel compounds
• X-Y model

We have investigated the antiferromagnetic (AF) phase transition and spin correlations in NiO by high-temperature neutron diffraction below and above T(N). We show that AF phase transition is a continuous second-order transition within our experimental resolution. The spin correlations manifested by the strong diffuse magnetic scattering persist well above T(N)approximate to 530 K and could still be observed at T=800 K which is about 1.5T(N). We argue that the strong spin correlations above T(N) are due to the topological frustration of the spins on a fcc lattice. The Neel temperature is substantially reduced by this process. We determined the critical exponents beta=0.328 /- 0.002 and nu=0.64 /- 0.03 and the Neel temperature T(N)=530 /- 1 K. These critical exponents suggest that NiO should be regarded as a 3dXY system.

• 出版日期2009-5