Magnetic phase diagram of the diluted metamagnet Fe\u3csub\u3e0.95\u3c/sub\u3eMg\u3csub\u3e0.05\u3c/sub\u3eBr\u3csub\u3e2\u3c/sub\u3e

The axial magnetic phase diagram of the antiferromagnet Fe0.95Mg0.05Br2 is studied by specific heat, superconducting quantum interference device, and Faraday rotation techniques. The diamagnetic impurities give rise to random-field criticality along the second-order phase line Hc(T) between TN=13.1 K and a multicritical point at Tm≈5 K, and to a spin-flop line between Tm and the critical end-point temperature Te≈3.5 K. The phase line H1(T)c(T) ending at Tm is probably due to symmetric nondiagonal exchange

Neutron scattering study of transverse magnetism

In order to clarify the nature of the additional phase transition at H1 (T) \u3c Hc (T) of the layered antiferromagnetic (AF) insulator FeBr2 as found by Aruga Katori et al. (1996) we measured the intensity of different Bragg-peaks in different scattering geometries. Transverse AF ordering is observed in both AF phases, AFI and AFII. Its order parameter exhibits a peak at T1 = T (H1) in temperature scans and does not vanish in zero field. Possible origins of the step-like increase of the transverse ferromagnetic ordering induced by a weak in-plane field component when entering AFI below T1 are discussed

Low-temperature properties of the spin-1 antiferromagnetic Heisenberg chain with bond-alternation

We investigate the low-temperature properties of the spin-1 antiferromagnetic Heisenberg chain with bond-alternation by the quantum Monte Carlo method (loop algorithm). The strength of bond-alternation at the gapless point is estimated as $\delta_{c}=0.2595\pm0.0005$. We confirm numerically that the low-temperature properties at the gapless point are consistent with field theoretical predictions. The numerical results are compared with those of the spin-1/2 antiferromagnetic Heisenberg chain and recent experimental results for [\{Ni(333-tet)($\mu$-N$_3$)\}$_n$](ClO$_4$)$_n$ (333-tet=tetraamine $N,N^{\prime}$-bis(3-aminopropyl)-1,3-propanediamine).Comment: 18 pages, RevTex, 9 figures, Submitted to Phys.Rev.

Neutron scattering study of transverse magnetism in the metamagnet FeBr₂

International audienceIn order to clarify the nature of the additional phase transition at H1(T) < Hc(T) of the layered antiferromagnetic (AF) insulator FeBr2as found by Aruga Katori et al. (1996) we measured the intensity of different Bragg-peaks in different scattering geometries. Transverse AF ordering is observed in both AF phases, AF I and AF II. Its order parameter exhibits a peak at T1= T(H1) in temperature scans and does not vanish in zero field. Possible origins of the step-like increase of the transverse ferromagnetic ordering induced by a weak in-plane field component when entering AF I below T1 are discussed

Neutron scattering study of transverse magnetism in the metamagnet

In order to clarify the nature of the additional phase transition at $H_{1}(T) < H_{\mathrm{c}}(T)$ of the layered antiferromagnetic (AF) insulator $\mathrm{FeBr}_{2}$ as found by Aruga Katori et al. (1996) we measured the intensity of different Bragg-peaks in different scattering geometries. Transverse AF ordering is observed in both AF phases, AF I and AF II. Its order parameter exhibits a peak at $T_{1} = T (H_{1})$ in temperature scans and does not vanish in zero field. Possible origins of the step-like increase of the transverse ferromagnetic ordering induced by a weak in-plane field component when entering AF I below T1 are discussed

Neutron scattering study of transverse magnetism in the metamagnet FeBr 2

PACS. 75.25.+z Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source X-ray scattering, etc.), 75.30.Kz Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.), 75.50.Ee Antiferromagnetics,