Transport measurements of the spin-wave parameters of thin Mn films

Temperature-dependent transport measurements on ultrathin antiferromagnetic Mn films reveal a heretofore unknown nonuniversal weak-localization correction to the conductivity which extends to disorder strengths greater than $100\mathrm{k}\Omega$ per square. The inelastic scattering of electrons off of gapped antiferromagnetic spin waves gives rise to an inelastic scattering length which is short enough to place the system in the three-dimensional regime. The extracted fitting parameters provide estimates of the energy gap ($\Delta \approx 16\mathrm{K}$) and Heisenberg exchange constant ($J\approx 1000\mathrm{K}$).

Figure 1

The temperature-dependent normalized conductivity (open squares) for two samples with the indicated disorder strengths of $R_0=$ $17573$ $\Omega$ and $63903$ $\Omega$ show good agreement with theory (solid lines). The fitting parameters $A$ and $B$ are indicated for each curve, with the error in the least significant digit indicated in parentheses.

Figure 2

Dependence of the fitting parameters $B$ and $A$ (inset) on disorder $R_0$ for $\Delta =$ 16 K. The fitting parameters are indicated for each curve, with the error in the least significant digit indicated in parentheses. Each of the 26 points in the main panel and in the inset represents a two-parameter fit ($A$ and $B$) to 26 temperature sweeps at different stages of disorder, two of which are shown in Fig. 1.