Electrical resistivity of the μ-Al₄Mn giant-unit-cell complex metallic alloy

Abstract

The μ-Al₄Mn complex intermetallic phase with 563 atoms in its giant unit cell exhibits a complicated temperature dependence of electrical resistivity that has a broad maximum at about 175 K and a minimum at 13 K. The temperature dependence of the resistivity was reproduced by employing the theory of quantum transport of slow charge carriers, which predicts a crossover from the metallic (Boltzmann-type) positive-temperature-coefficient electrical resistivity at low temperatures to the insulator-like (non-Boltzmann) negative-temperature-coefficient resistivity at elevated temperatures. The low-temperature resistivity minimum was reproduced by considering it as a magnetic effect due to increased scattering of the conduction electrons by the Mn spins on approaching the spin glass phase that develops below the spin freezing temperature T_f = 2.7 K.

Keywords:

• complex metallic alloy
• electrical resistivity
• Al–Mn system
• magnetic susceptibility
• spin glass

Acknowledgements

This work was performed within the 6th Framework EU Network of Excellence “Complex Metallic Alloys” (Contract No. NMP3-CT-2005-500140). J.D. acknowledges support from the Centre of Excellence EN → FIST, Dunajska 156, SI-1000 Ljubljana, Slovenia.

Notes

^†On leave from the Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland

Additional information

Notes on contributors

M. Wencka†

†On leave from the Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland