Nature of magnetic interactions in β-Co(OH)₂ nanoparticles

Abstract

Magnetic properties of β‐Co(OH)2 nanoparticles covering temperature range of 5–300 K in magnetic field upto 50 kG are studied. Zero‐field‐cooled and field‐cooled susceptibility as a function of temperature curves in different applied magnetic fields are seen to bifurcate at Tbf=11thinmathspacenormalK. Curie–Weiss fit of zero‐field‐cooled susceptibility curve well above Tbf yields θ=9thinmathspacenormalK and ionic magnetic moment μ=5.03thinmathspaceμB. Magnetization as a function of applied magnetic field curve below Tbf shows a two‐step transition to ferromagnetic state. Strength of three possible exchange interactions among Co2+ ions in β‐Co(OH)2 nanoparticles is also determined. We find that the present system orders antiferromagnetically at TN=11thinmathspacenormalK, with a dominant intralayer ferromagnetic coupling and a weaker interlayer antiferromagnetic coupling.

Magnetic Ground State and Tunable Néel Temperature in the Spin ½ Linear Chain Antiferromagnet Co(OH)(2−x)Fx

“…Transition metals in compounds play key roles in their physical and chemical properties such as magnetism [1][2][3][4][5][6][7][8] and electrochemical performance. [9][10][11] The magnetism of matter arises from the intrinsic magnetic moment of atoms (namely, unpaired and paired electrons around atoms).…”

Magnetic investigations of phase transitions, exchange interactions, and magnetic ground state in nanosheets ofβ-Co(OH)2

“…In this paper, we report the results of our investigations into the nature of magnetism in β-Co(OH) 2 . The fact that β-Co(OH) 2 orders antiferromagnetically below T N = 9 K to 12 K depending on the crystallite size is not in question [1][2][3][8][9][10][11]. However, whether β-Co(OH) 2 is a spin S = 3/2 system following Hunds' rules as recent paper by Gupta et al [11] and Nielson et al [16] have mentioned or a system with an effective spin S = 1/2 [2,17] is not completely settled.…”

“…The fact that β-Co(OH) 2 orders antiferromagnetically below T N = 9 K to 12 K depending on the crystallite size is not in question [1][2][3][8][9][10][11]. However, whether β-Co(OH) 2 is a spin S = 3/2 system following Hunds' rules as recent paper by Gupta et al [11] and Nielson et al [16] have mentioned or a system with an effective spin S = 1/2 [2,17] is not completely settled. Consequently, the magnitudes of the in-plane exchange constant J 1 and interplane exchange constant J 2 given by different investigations are also quite different [2,11].…”

“…However, whether β-Co(OH) 2 is a spin S = 3/2 system following Hunds' rules as recent paper by Gupta et al [11] and Nielson et al [16] have mentioned or a system with an effective spin S = 1/2 [2,17] is not completely settled. Consequently, the magnitudes of the in-plane exchange constant J 1 and interplane exchange constant J 2 given by different investigations are also quite different [2,11]. Also, the observed magnetic-field induced transition near 15 kOe has been termed spin-flop transition by some [16] and metamagnetic transition by others [2].…”

“…The magnetic properties of layered hydroxides of Ni, Co, and Cu with the CdI 2 hexagonal structure have been the subject of active investigations for some time [1][2][3][4][5][6][7][8][9][10][11]. This is because the nature of magnetism depends not only on the 3d magnetic ions but also on the interaction between the hexagonal layers, the latter varied by intercalating different molecules between the layers [2,3].…”