Ferromagnetism of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow><mml:mi>e</mml:mi></mml:math>Films in the Low-Field Limit

Bozler, H. M.; Gu, Yuan; Zhang, Jinshan; White, K. S.; Gould, C. M.

doi:10.1103/physrevlett.88.065302

Cited by 11 publications

(4 citation statements)

References 24 publications

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“…Previous measurements of the magnetization of the second layer at 0.03-0.48 mT have been interpreted as a finite temperature phase transition [29]. We note that these magnetic fields are comparable to or smaller than the spin-flop field.…”

supporting

confidence: 47%

Two-Dimensional Ferromagnetism of aHe3Film: Influence of Weak Frustration

et al. 2013

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(3)He films adsorbed on the atomically flat surface of graphite provide a model system for the study of two-dimensional magnetism on a triangular lattice. We have made a study of the regime in which the T=0 ground state of the second (3)He layer is a fully polarized ferromagnet. NMR, using broadband SQUID detection, at a range of low fields above the spin-flop transition, and over a wide temperature range 0.3-200 mK, has enabled us to disentangle the influence of sample finite size effects and magnetic field on the spin-wave spectrum. We demonstrate that the spin-wave spectrum is governed by a different effective exchange constant than that determining the high temperature magnetism. This is understood in terms of frustrated atomic ring exchange.

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supporting

confidence: 47%

Two-Dimensional Ferromagnetism of aHe3Film: Influence of Weak Frustration

et al. 2013

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“…The 20% deficit was interpreted as the likely existence of non-FM spins trapped at stronger potential sites caused by the substrate heterogeneities. The more recent magnetization measurement for smaller FM islands laterally compressed by 4 He atoms on 4 He preplated Grafoil 83) and measurement in much lower magnetic fields 84) reported nearly the full saturation [MðT ¼ 0Þ % M sat ]. The heterogeneity effect is expected to be minimized in the former experiment.…”

Section: Special Topicsmentioning

confidence: 99%

“…It is an interesting question whether finite temperature transitions occur or not in extremely low fields. Bozler et al 84) claimed FM phase transitions occur at finite temperatures of T % J in extremely low fields (B 0:48 mT) at densities corresponding to the coexistence between the 4/7 phase and the C2 phase. This claim is based on their observations of rapid increase of magnetization near those temperatures and the diminishing field dependence of magnetization below them.…”

Section: Special Topicsmentioning

confidence: 99%

Nuclear Magnetism in Two-Dimensional Solid Helium Three on Graphite

Fukuyama

2008

J. Phys. Soc. Jpn.

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Recent studies of nuclear magnetism of monolayer helium three ( 3 He) adsorbed on graphite are reviewed. This system provides us a fascinating testing ground for physics of highly frustrated quantum spins of two dimensions (2D) such as spin liquids. Particular emphasis is devoted to the gapless spin liquid state observed in the low-density commensurate phase (4/7 phase) in the second layer. Existing experiments on heat capacity in zero magnetic field and magnetization in low fields of this phase show unambiguously the gapless excitations down to three orders of magnitude lower temperatures than the relevant exchange interactions (%1 mK). This is a new class of spin liquid, and recently electronic counterparts are found in quasi-1D and -2D conductors. On the other hand, measured magnetic properties of the incommensurate phase at much higher densities can be described as a nearly ideal 2D S ¼ 1=2 ferromagnet on a triangular lattice. We propose the existence of a new ferromagnetic commensurate phase at a density in between the 4/7 and incommensurate phases based on new heat capacity data. None of these phases show signatures of finite temperature phase transitions being consistent with the MerminWagner theorem. The exchange interactions among 3 He nuclear spins originate from atom-atom tunnel exchanges due to the large zero-point motions. Because of the steric hindrance, higher order exchanges like three-, four-, five-, and six-spin ring exchanges are expected to compete each other in similar strengths (MSE model). The applicability of the MSE model to the experimental magnetic properties of this system including its density variation is discussed. It is satisfactory except the fact that the model does not reproduce the gapless nature of the 4/7 phase, which recently stimulates different theoretical approaches such as the Hubbard model.

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“…Excellent experiments have been performed on thin films of various ferromagnetic materials ranging from iron to gadolinium and a wide range of ordering effects has been observed [6,8,12]. These measurements have also demonstrated the existence of a spontaneous magnetization and have revealed hysteresis curves in two- [11,[13][14][15][16] or one-dimensional [17] systems, where magnetic ions are arranged in a grid or a line within a monolayer. However, one can argue that the apparent contradiction between theory and experiment basically arises due to the fact that the ferromagnetic monolayers are not an ideal two-dimensional (2D) system primarily because monolayers are intrinsically anisotropic.…”

Section: Introductionmentioning

confidence: 97%

Two-dimensional magnetic ordering in a multilayer structure

Mukhopadhyay

Sanyal

2006

Pramana - J Phys

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The effect of confinement from one, two or from all three directions on magnetic ordering has remained an active field of research for almost 100 years. The role of dipolar interactions and anisotropy are important to obtain, the otherwise forbidden, ferromagnetic ordering at finite temperature for ions arranged in two-dimensional (2D) arrays (monolayers). We have demonstrated that conventional low-temperature magnetometry and polarized neutron scattering measurements can be performed to study short-range ferromagnetic ordering of in-plane spins in 2D systems using a multilayer stack of noninteracting monolayers of gadolinium ions formed by Langmuir-Blodgett (LB) technique. The spontaneous magnetization could not be detected in the heterogeneous magnetic phase observed here and the saturation value of the net magnetization was found to depend on the sample temperature and applied magnetic field. The net magnetization rises exponentially with lowering temperature and then reaches saturation following a T ln(βT ) dependence. The T ln(βT ) dependence of magnetization has been predicted from spinwave theory of 2D in-plane spin system with ferromagnetic interaction. The experimental findings reported here could be explained by extending this theory to a temperature domain of βT < 1.

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Ferromagnetism ofH3eFilms in the Low-Field Limit

Cited by 11 publications

References 24 publications

Two-Dimensional Ferromagnetism of aHe3Film: Influence of Weak Frustration

Two-Dimensional Ferromagnetism of aHe3Film: Influence of Weak Frustration

Nuclear Magnetism in Two-Dimensional Solid Helium Three on Graphite

Two-dimensional magnetic ordering in a multilayer structure

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