Theory of nuclear spin interactions in ferromagnetic insulators. I. The thermodynamic properties

Cottam, M. G.; Jones, M. J.

doi:10.1088/0022-3719/6/6/015

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…Hole-nuclear spin interaction is of type AI.S (A = hyperfine splitting constant, I = nuclear spin, S = hole spin). The correction due to this effect on exchange interaction has been calculated by Cottam et al [25]. who found it to be quite small and proportional to AT 1/2 .…”

Section: Orderparameter Of the Hole-pairmentioning

confidence: 93%

Model of Preformed Hole-Pairs in Cuprate Superconductors

Singh¹

2011

JMP

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A model of preformed hole-pairs in cuprate superconductors has been proposed based on some experimental results i.e., 1) electron paramagnetic resonance spectra of quenched superconductors which show very frequently the fragment (CuO) 4 broken off from the CuO 2 layer in the structure, 2) 41 meV peak observed in neutron diffraction and nuclear magnetic resonance spectra of superconductors, 3) Heisenberg exchange interaction leading to ferromagnetism observed in CuO which is an essential ingredient of all superconductors and some generally accepted conclusions i.e., a) that the order parameter in superconductors has 2 2 x y d  symmetry and b) coherence length is of the order of 15 -20 Angstrom. Heisenberg exchange interaction between two (CuO 4 ) plaquettes each containing a lattice hole binds the two holes which are the charge carriers in the cuprate superconductors. It is not very clear whether the hole-pair is in the triplet or singlet state, but the triplet state is supported by the experimental observation of ferromagnetism in the parent material CuO. The proposed hole-pair singlet is different from Zhang-Rice singlet.

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Section: Orderparameter Of the Hole-pairmentioning

confidence: 93%

Model of Preformed Hole-Pairs in Cuprate Superconductors

Singh¹

2011

JMP

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“…Our aim here is to study the strongly nonequilibrium regimes of spin motion. This problem is different from considering the equilibrium properties of coupled electron and nuclear spins [23][24][25][26]. An additional complication, in our case, arises from the coupling of spins with a resonator by means of the feedback equation (25).…”

Section: Scale Separation Approachmentioning

confidence: 92%

“…Then Eqs. ( 22), (23), and (24) show that the variables s and |u| 2 are slow compared to the fast variable u. As the nuclear magnetic moment µ n is much smaller than that of an electron, µ e , we have the inequalities…”

Section: Scale Separation Approachmentioning

confidence: 98%

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Nonlinear spin dynamics in ferromagnets with electron-nuclear coupling

1999

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Nonlinear spin motion in ferromagnets is considered with nonlinearity due to three factors: (i) the sample is prepared in a strongly nonequilibrium state, so that evolution equations cannot be linearized as would be admissible for spin motion not too far from equilibrium, (ii) the system considered consists of interacting electron and nuclear spins coupled with each other via hyperfine forces, and (iii) the sample is inserted into a coil of a resonant electric circuit producing a resonator feedback field. Due to these nonlinearities, coherent motion of spins can develop, resulting in their ultrafast relaxation. A complete analysis of mechanisms triggering such a coherent motion is presented. This type of ultrafast coherent relaxation can be used for studying intrinsic properties of magnetic materials.

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“…In both cases, the resonant frequency falls from 4t to 3t at high stress where we have again neglected the population of the upper levels. This seems broadly consistent with the data points in figure 10(b) which suggest a rather weak dependence of w o on stress at least up to 1000 kgf cm-2 and to obtain a value of VTb we return to figure 5 which shows that at 1.8 K saturation is reached at 1000 kgf cm-2, We first consider V, < 0 and in calculating the energy levels we assume K(T2) has its limiting value of 6 and take s44 = 1.66 X lo-" m2 N-' (these values of the elastic constants are from Cottam and Saunders (1973)). The data suggest that 1 VTb 1 > 20 000 cm-' since for this value the separation of the lower two levels at 1000 kgf cm-' is only 79% of 3t so that saturation is still incomplete.…”

Section: Determination Of the Lattice Coupling Constants Veb And Vbmentioning

confidence: 99%

Phonon studies of Ni²⁺in GaAs:evidence for an orthorhombic Jahn-Teller system

Challis¹,

Salce²,

Butler³

et al. 1989

J. Phys.: Condens. Matter

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Thermal conductivity measurements have been made from 50 mK to 100 K of Ni-doped GaAs samples containing different proportions of Ni+, Ni2+ and Ni3+. Resonant phonon scattering at 300 GHz is assigned to Ni2+ (3T1) and this is supported by studies of photoinduced changes in the Ni2+ concentration. The scattering is attributed to tunnelling within the ground state of an orthorhombic Jahn-Teller system. Uniaxial stress measurements show that the levels are very sensitive to both E and T2 strains and provide values of VEb and VTb. Data for Cr3+(4T1) in GaAs, GaP and InP are re-examined in the light of these results. It is proposed that the rich spectrum of resonance frequencies is due to multiple-ion effects caused by ion-ion coupling via the strain field.

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Theory of nuclear spin interactions in ferromagnetic insulators. I. The thermodynamic properties

Cited by 8 publications

References 15 publications

Model of Preformed Hole-Pairs in Cuprate Superconductors

Model of Preformed Hole-Pairs in Cuprate Superconductors

Nonlinear spin dynamics in ferromagnets with electron-nuclear coupling

Phonon studies of Ni²⁺in GaAs:evidence for an orthorhombic Jahn-Teller system

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Theory of nuclear spin interactions in ferromagnetic insulators. I. The thermodynamic properties

Cited by 8 publications

References 15 publications

Model of Preformed Hole-Pairs in Cuprate Superconductors

Model of Preformed Hole-Pairs in Cuprate Superconductors

Nonlinear spin dynamics in ferromagnets with electron-nuclear coupling

Phonon studies of Ni2+in GaAs:evidence for an orthorhombic Jahn-Teller system

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Phonon studies of Ni²⁺in GaAs:evidence for an orthorhombic Jahn-Teller system