### Session B33: Cooperative Phenomena Theory

11:15 AM–2:15 PM, Monday, March 15, 2010
Room: E143

Chair: Chia-Ren Hu, Texas A&M University

Abstract ID: BAPS.2010.MAR.B33.12

### Abstract: B33.00012 : Anomalous Pinning Fields in Helical Magnets

1:27 PM–1:39 PM

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#### Authors:

D. Belitz
(Department of Physics, and Institute of Theoretical Science, University of Oregon, Eugene, OR 97403)

T.R. Kirkpatrick
(Institute for Physical Science and Technology, and Department of Physics, University of Maryland, College Park, MD 20742)

The spin-orbit interaction strength $g_{\textrm{so}}$ in helical magnets determines both the pitch wave number $q$ and the critical field $H_{\textrm{c1}}$ where the helix aligns with an external magnetic field. Within a standard Landau-Ginzburg-Wilson (LGW) theory, a determination of $g_{\textrm{so}}$ in MnSi and FeGe from these two observables yields values that differ by a factor of $20$. This discrepancy is remedied by considering the fermionic theory underlying the LGW theory, and in particular the effects of screening on the effective electron-electron interaction that results from an exchange of helimagnons [1]. \\[4pt] $[1]$ T.R. Kirkpatrick and D. Belitz, Phys. Rev. B, in press.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.B33.12