Magnetic phase diagram of three-dimensional diluted Ising antiferromagnet Ni$_{0.8}$Mg$_{0.2}$(OH)$_{2}$

Masatsugu Suzuki; Itsuko S. Suzuki; Tedmann M. Onyango; Toshiaki Enoki

doi:10.1143/JPSJ.73.206

paper

Magnetic phase diagram of three-dimensional diluted Ising antiferromagnet Ni $_{0.8}$ Mg $_{0.2}$ (OH) $_{2}$

arXiv:cond-mat/0309354 · doi:10.1143/JPSJ.73.206

Abstract

$H$ - $T$ diagram of 3D diluted Ising antiferromagnet Ni $_{c}$ Mg $_{1 - c}$ (OH) $_{2}$ with $c$ = 0.8 has been determined from measurements of SQUID DC magnetization and AC magnetic susceptibility. At $H$ = 0, this compound undergoes two magnetic phase transitions: an antiferromagnetic (AF) transition at the Néel temperature $T_{N}$ (= 20.7 K) and a reentrant spin glass (RSG) transition at $T_{R S G}$ ( $\approx$ 6 K). The $H$ - $T$ diagram consists of the RSG, spin glass (SG), and AF phases. These phases meet a multicritical point $P_{m}$ ( $H_{m}$ = 42 kOe, $T_{m}$ = 5.6 K). The irreversibility of susceptibility defined by $δ$ (= $χ_{F C} - χ_{Z F C}$ ) shows a negative local minimum for 10 $\leq H \leq$ 35 kOe, suggesting the existence of possible glassy phase in the AF phase. A broad peak in $δ$ and $χ^{''}$ at $H \geq$ 20 kOe for $T_{N} (c = 0.8, H) \leq T \leq T_{N} (c = 1, H = 0)$ (= 26.4 K) suggests the existence of the Griffiths phase.

11 pages, 14 figures; J. Phys. Soc. Jpn. 73 (2004) No. 1 issue, in press

Magnetic phase diagram of three-dimensional diluted Ising antiferromagnet Ni0.8​Mg0.2​(OH)2​

Abstract

Magnetic phase diagram of three-dimensional diluted Ising antiferromagnet Ni $_{0.8}$ Mg $_{0.2}$ (OH) $_{2}$