N M R Peres
Departamento de Física and GCEP-Centro de Física da Universidade do Minho, Campus Gualtar, P-4700-320 Braga, Portugal
Journal of Physics: Condensed Matter Create an alert RSS this journal
N M R Peres 2003 J. Phys.: Condens. Matter 15 7271
In this paper we compute the mean field phase diagram of a doped antiferromagnet, in a magnetic field and with anisotropic exchange. We show that at zero temperature there is a metamagnetic transition from the antiferromagnetic configuration along the z direction to a spin flop (SF) state. In the spin flop phase the system prefers a commensurate magnetic order, at low doping, whereas at larger doping the incommensurate phase is favourable. Contrary to the pure Heisenberg case, the spin flop region does not span an infinite area in the (Δ,h) plane, where Δ is the exchange anisotropy and h is the external magnetic field. We characterize the magnetic and charge-transport properties of the SF phase, computing the magnetic susceptibility and the Drude weight. This latter quantity presents a sudden variation as the SF to paramagnet phase transition line is crossed. This effect could be used as a possible source of large magneto-resistance. Our findings may have some relevance for doped La2−δSrδCuO4 in a magnetic field.
75.30.Cr Saturation moments and magnetic susceptibilities
75.30.Et Exchange and superexchange interactions
75.30.Kz Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.)
Issue 43 (5 November 2003)
Received 22 May 2003
Published 17 October 2003
N M R Peres 2003 J. Phys.: Condens. Matter 15 7271
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