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Lattice dynamics of antiperovskite manganese nitrides exhibiting large negative and positive thermal expansion

ORAL

Abstract

Antiperovskite manganese nitrides Mn3AN (where A is a metal or semiconducting element) have strong charge-spin-lattice interactions resulting in magnetovolume effects such as large positive (PTE) and negative thermal expansion (NTE) over transitions between their ferrimagnetic, antiferromagnetic, and paramagnetic phases [1]. We grow films of Mn3Cu1-xGexN with x = 0.1 to 0.5, which exhibit tunable NTE coefficients over a 50 K region, occurring anywhere from around 100 K to around 400 K depending on x. We also grow films of Mn3Cu1-xNixN with x = 0.09 to 0.10, which have a first order hysteretic PTE of 1-1.5% near 100 K and exhibit NTE for a total lattice contraction of roughly 0.5% over a 25 K range around 175 K. These regions are linked to transitions in magnetic phases. To probe the coupling of the structure and magnetism, we have measured the X-ray diffraction following photoexcitation within and through the interesting regions at the Advanced Photon Source. We present the complex lattice dynamics and discuss the spin-lattice coupling driving their response.

[1] Takenaka, K., et al. Appl. Phys. Lett. 87, 261902 (2005).

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Presenters

  • Sheena Patel

    University of California, San Diego, Physics, University of California San Diego

Authors

  • Sheena Patel

    University of California, San Diego, Physics, University of California San Diego

  • Stjepan B Hrkac

    University of California, San Diego

  • Jeffrey Brock

    University of California, San Diego, Center for Memory and Recording Research, University of California, San Diego

  • Nelson Hua

    University of California, San Diego

  • Haidan Wen

    Argonne National Laboratory, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA, Advanced Photon Source, Argonne National Laboratory

  • Oleg Shpyrko

    University of California, San Diego

  • Eric Fullerton

    University of California, San Diego, Center for Magnetic Recording Research, University of California at San Diego, Center for Memory and Recording Research, University of California, San Diego, CMRR, University of California San Diego, Center for Memory and Recording research, UCSD