Spin dynamics of EuO in the paramagnetic phase

Chaudhury, Ranjan; Shastry, B. Sriram

doi:10.1103/physrevb.37.5216

Cited by 20 publications

(19 citation statements)

References 22 publications

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“…Magnon modes are low energy excitations and represent a quantized coherent precessional motion of all the spins around the direction of the spontaneous magnetization in the long range ordered phase. These modes however, become ill-defined in the short range ordered phase [45][46][47][48]. In contrast, the quantum states representing topological spin excitations are found to be stable even in the short range ordered phase when the system size is very large, as we will demonstrate in this communication.…”

Section: Introductionmentioning

confidence: 76%

The connection between vortex-like topological excitations and conventional excitations in quantum ferromagnetic spin systems on two-dimensional lattice and their stability

Sarkar

Chaudhury

Paul

2015

Int. J. Mod. Phys. B

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Abstract:We present a scheme for the construction of quantum states of vortex like topological excitations corresponding to spin-½ strongly XY anisotropic nearest neighbor Heisenberg Ferromagnet on two dimensional lattice. The procedure involving Pauli spin basis states is carried out corresponding to both infinite dilute limit and finite density limit of vortex/anti-vortex. It is found that the corresponding quantum mechanical states representing charge 1 quantum vortices/ anti-vortices can be expressed as linear combinations of single magnon states, composite multi-magnon states and the ground state. Detailed calculations show that these states are quantum mechanically stable states of the Hamiltonian only when the system size exceeds certain threshold value. Our analysis indicates that the interactions between different magnon modes can very well generate these topological excitations. Possible applications of our calculations to real magnetic systems are also discussed. Magnetic measurements probing spin dynamics may be undertaken to verify the existence of the threshold size for the stability of vortices.

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Section: Introductionmentioning

confidence: 76%

The connection between vortex-like topological excitations and conventional excitations in quantum ferromagnetic spin systems on two-dimensional lattice and their stability

Sarkar

Chaudhury

Paul

2015

Int. J. Mod. Phys. B

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“…INS investigations of the spin dynamics in EuO have undoubtedly proven the presence of finite spin correlations above T C up to 115 K [16,17,42]. Well defined but heavily damped spin waves above T C at the zone boundaries, mediated by exchange between nearest and next nearest neighbor Eu ions, have been experimentally observed [16,17] and theoretically confirmed [20], similar to Fe [43], Ni [44], and double perovskites [45].…”

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confidence: 85%

Lattice Dynamics of EuO: Evidence for Giant Spin-Phonon Coupling

et al. 2016

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“…Such a behaviour is quite typical of localised twodimensional magnetic systems and has been observed before [24,25]. The indications of persistent spin waves above T C have been obtained in three-dimensional ideal Heisenberg ferromagnet EuO and EuS both experimentally [26] and also by calculations using Monte Carlo molecular dynamics technique [27].…”

mentioning

confidence: 83%