Quantitative Studies of Spin-Momentum-Transfer-Induced Excitations in Co/Cu Multilayer Films Using Point-Contact Spectroscopy

Published

February 24, 2003

Author(s)

William Rippard, Matthew Pufall, Thomas J. Silva

Abstract

We have measured current-induced magnetic excitations in a variety of exchange-coupled Co/Cu multilayers using point-contact spectroscopy. A step in the DC resistance and corresponding peak in dV/dI are observed at a critical current Ic whose value linearly depends applied magnetic field B, in agreement with Slonczewski's theory. These features are observed for both in- and out of plane fields. Excitations in ferromagnetically-coupled films occur even without an applied field. The spin transfer efficiency is determined from the slope and intercept of Ic vs. Bapp and varied from contact-to-contact. These variations are within the range predicted by Slonczewski's theory, as bounded between the diffusive and ballistic limits for electron propagation through a point contact.

Citation

Applied Physics Letters

Volume

82

Issue

8

Pub Type

Journals

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Keywords

point contact, SMT, spin excitations, spin momentum transfer

Citation

Rippard, W. , Pufall, M. and Silva, T. (2003), Quantitative Studies of Spin-Momentum-Transfer-Induced Excitations in Co/Cu Multilayer Films Using Point-Contact Spectroscopy, Applied Physics Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=30853 (Accessed October 14, 2025)