### Abstract

We begin with a brief history of magnetoviscosity measurements in materials. We then show that the relaxation of the thermoremanent magnetization in spin glasses is accurately characterized, over several decades in time, by the stretched exponential: σ_{TRM}=σ_{0} exp[-C(ωt)^{1-n}/(1-n)]. The time-stretch exponent (n) is given as a function of temperature for both 2.6% AgMn+0.46% Sb and 1.0% CuMn; dissimilarities in the temperature dependence of n may be due to the different anisotropy energy of the samples. We emphasize the experimental fact that a field-cooled sample is not in equilibrium and show that the time development of the field-cooled state may be characterized as an exponential decrease of the relaxation frequency with increasing wait time: ω=ω_{0} exp(-t_{w}/t_{0}). We briefly outline three general theories which have the stretched-exponential time dependence, but no theory can yet explain all of the observed behavior in spin glasses. We conclude by showing that the remanent magnetization in a ferromagnet may also have the stretched-exponential time dependence.

Original language | English (US) |
---|---|

Pages (from-to) | 3377-3381 |

Number of pages | 5 |

Journal | Journal of Applied Physics |

Volume | 57 |

Issue number | 8 |

DOIs | |

State | Published - 1985 |

Externally published | Yes |

### Fingerprint

### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)

### Cite this

**Time decay of the remanent magnetization in spin glasses (invited).** / Chamberlin, Ralph.

Research output: Contribution to journal › Article

*Journal of Applied Physics*, vol. 57, no. 8, pp. 3377-3381. https://doi.org/10.1063/1.335102

}

TY - JOUR

T1 - Time decay of the remanent magnetization in spin glasses (invited)

AU - Chamberlin, Ralph

PY - 1985

Y1 - 1985

N2 - We begin with a brief history of magnetoviscosity measurements in materials. We then show that the relaxation of the thermoremanent magnetization in spin glasses is accurately characterized, over several decades in time, by the stretched exponential: σTRM=σ0 exp[-C(ωt)1-n/(1-n)]. The time-stretch exponent (n) is given as a function of temperature for both 2.6% AgMn+0.46% Sb and 1.0% CuMn; dissimilarities in the temperature dependence of n may be due to the different anisotropy energy of the samples. We emphasize the experimental fact that a field-cooled sample is not in equilibrium and show that the time development of the field-cooled state may be characterized as an exponential decrease of the relaxation frequency with increasing wait time: ω=ω0 exp(-tw/t0). We briefly outline three general theories which have the stretched-exponential time dependence, but no theory can yet explain all of the observed behavior in spin glasses. We conclude by showing that the remanent magnetization in a ferromagnet may also have the stretched-exponential time dependence.

AB - We begin with a brief history of magnetoviscosity measurements in materials. We then show that the relaxation of the thermoremanent magnetization in spin glasses is accurately characterized, over several decades in time, by the stretched exponential: σTRM=σ0 exp[-C(ωt)1-n/(1-n)]. The time-stretch exponent (n) is given as a function of temperature for both 2.6% AgMn+0.46% Sb and 1.0% CuMn; dissimilarities in the temperature dependence of n may be due to the different anisotropy energy of the samples. We emphasize the experimental fact that a field-cooled sample is not in equilibrium and show that the time development of the field-cooled state may be characterized as an exponential decrease of the relaxation frequency with increasing wait time: ω=ω0 exp(-tw/t0). We briefly outline three general theories which have the stretched-exponential time dependence, but no theory can yet explain all of the observed behavior in spin glasses. We conclude by showing that the remanent magnetization in a ferromagnet may also have the stretched-exponential time dependence.

UR - http://www.scopus.com/inward/record.url?scp=0041429925&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0041429925&partnerID=8YFLogxK

U2 - 10.1063/1.335102

DO - 10.1063/1.335102

M3 - Article

AN - SCOPUS:0041429925

VL - 57

SP - 3377

EP - 3381

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 8

ER -