1. Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
2. Department of Physics, Center for the Physics of Materials, McGill University, Montreal, Quebec H3A 2T8, Canada
3. Ecole Polytechnique de Montreal, Montreal, Quebec H3T 1J4, Canada
4. Everspin Technologies, 1347 N. Alma School Road, Chandler, Arizona 85224, USA