1. Spin Device Technology Center, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
2. Center for Energy and Environmental Science, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
3. Precision and Electronics Technology Department, Nagano Prefecture General Industrial Technology Center, 1-3-1 Osachi Katama-Cho, Okaya 394-0084, Japan