### Abstract

The temperature dependence of EPR frequencies is studied theoretically for pure and pseudo-one dimensional Heisenberg magnets by means of Mori's theory of generalized Brownian motions. In a system with uniaxial symmetry, simple expressions for resonance frequencies are obtained. It is seen that the resonance frequencies are shifted from the Zeeman frequency when the magnetic susceptibility is anisotropic. Fisher's classical spin model is used to calculate the spin correlation functions. The anisotropy of the magnetic susceptibility is found to be enhanced by an effect of the short range order. The pseudo-one dimensional systems are treated with the help of the mean field approximation to interchain interactions. The result is reduced to that of a pure-one dimensional system, when the interchain interactions are absent. The effects of interchain interactions are negligible for antiferromagnets even near the Néel point, whereas those for ferromagnets are divergent near the Curie point. Nagata and Tazuke's expressions for a g-shift can be obtained from the present theory in an approximation.

Original language | English |
---|---|

Pages (from-to) | 1131-1136 |

Number of pages | 6 |

Journal | Journal of the Physical Society of Japan |

Volume | 43 |

Issue number | 4 |

DOIs | |

Publication status | Published - 1977 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Physics and Astronomy(all)

### Cite this

*Journal of the Physical Society of Japan*,

*43*(4), 1131-1136. https://doi.org/10.1143/JPSJ.43.1131

**Temperature Dependence of EPR Frequencies in Pure-and Pseudo-One Dimensional Heisenberg Magnets.** / Karasudani, Takashi; Okamoto, Hisao.

Research output: Contribution to journal › Article

*Journal of the Physical Society of Japan*, vol. 43, no. 4, pp. 1131-1136. https://doi.org/10.1143/JPSJ.43.1131

}

TY - JOUR

T1 - Temperature Dependence of EPR Frequencies in Pure-and Pseudo-One Dimensional Heisenberg Magnets

AU - Karasudani, Takashi

AU - Okamoto, Hisao

PY - 1977

Y1 - 1977

N2 - The temperature dependence of EPR frequencies is studied theoretically for pure and pseudo-one dimensional Heisenberg magnets by means of Mori's theory of generalized Brownian motions. In a system with uniaxial symmetry, simple expressions for resonance frequencies are obtained. It is seen that the resonance frequencies are shifted from the Zeeman frequency when the magnetic susceptibility is anisotropic. Fisher's classical spin model is used to calculate the spin correlation functions. The anisotropy of the magnetic susceptibility is found to be enhanced by an effect of the short range order. The pseudo-one dimensional systems are treated with the help of the mean field approximation to interchain interactions. The result is reduced to that of a pure-one dimensional system, when the interchain interactions are absent. The effects of interchain interactions are negligible for antiferromagnets even near the Néel point, whereas those for ferromagnets are divergent near the Curie point. Nagata and Tazuke's expressions for a g-shift can be obtained from the present theory in an approximation.

AB - The temperature dependence of EPR frequencies is studied theoretically for pure and pseudo-one dimensional Heisenberg magnets by means of Mori's theory of generalized Brownian motions. In a system with uniaxial symmetry, simple expressions for resonance frequencies are obtained. It is seen that the resonance frequencies are shifted from the Zeeman frequency when the magnetic susceptibility is anisotropic. Fisher's classical spin model is used to calculate the spin correlation functions. The anisotropy of the magnetic susceptibility is found to be enhanced by an effect of the short range order. The pseudo-one dimensional systems are treated with the help of the mean field approximation to interchain interactions. The result is reduced to that of a pure-one dimensional system, when the interchain interactions are absent. The effects of interchain interactions are negligible for antiferromagnets even near the Néel point, whereas those for ferromagnets are divergent near the Curie point. Nagata and Tazuke's expressions for a g-shift can be obtained from the present theory in an approximation.

UR - http://www.scopus.com/inward/record.url?scp=0005263198&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0005263198&partnerID=8YFLogxK

U2 - 10.1143/JPSJ.43.1131

DO - 10.1143/JPSJ.43.1131

M3 - Article

AN - SCOPUS:0005263198

VL - 43

SP - 1131

EP - 1136

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

SN - 0031-9015

IS - 4

ER -