Frequency dependence of the spin glass freezing temperatures in icosahedral R - Mg - Zn (R = rare earth) quasicrystals

TL;DR

This study investigates how the spin glass freezing temperatures in icosahedral R-Mg-Zn quasicrystals depend on measurement frequency, revealing different behaviors between Heisenberg and non-Heisenberg types due to magnetic anisotropy.

Contribution

It provides the first detailed frequency-dependent analysis of freezing temperatures in these quasicrystals, highlighting the role of magnetic anisotropy in non-Heisenberg spin glasses.

Findings

Gd-based Heisenberg spin glasses show ~2% increase in freezing temperature from 10 Hz to 10 kHz.

Non-Heisenberg spin glasses exhibit 16-22% increase over the same frequency range.

Magnetic anisotropy influences low-frequency magnetic dynamics in non-Heisenberg quasicrystals.

Abstract

We present ac susceptibility measurements with the frequency spanning three orders of magnitude on single grain, icosahedral R - Mg - Zn (R = rare earth) quasicrystals. The freezing temperature in Gd-based, Heisenberg spin glasses in this family increases by ~ 2% with a frequency increase from 10 Hz to 10 kHz, whereas the freezing temperature in the non-Heisenberg members of the family is significantly more responsive to the frequency change (by 16 - 22 %), suggesting that an additional magnetic anisotropy distribution in the non-Heisenberg spin glasses causes changes in the low frequency magnetic dynamics.