**Acknowledgements**

This work is supported by the program for research and development of smart magnetic material, Center for Science and Technology of Advanced Materials, National Nuclear Energy Agency. The authors are thankful to Prof. Dr. Ridwan and Dr. Abu Khalid Rivai, M.Eng., for their permission to publish this book chapter. Many thanks to Dra. Mujamilah, M.Sc., and Drs. Bambang Sugeng for their kind help to characterize using VSM and XRD, respectively.
