Spintronic devices provide new features and better performance than conventional semiconductor-based electronic devices due to which they find applications in magnetic random access memory (MRAM), spin transistors, spin filters and sensors. Spintronic devices use the intrinsic spin of electrons to process and encode data and provide non-volatile memory capacities and high-speed data access, which is essential to industry data storage technologies like hard disk drives (HDDs) and solid-state drives (SSDs). The spin-dependent significances in spintronic devices arise due to interaction between magnetic properties and spin transport properties of the material. Spintronic devices also aid in the development of spin-based logic circuits for next-generation computing architectures and spin-based oscillators. From the last few years, spintronic devices have also been used for biosensing applications as diagnostic instruments in biomedical fields to detect biomolecules and analyse DNA sequences with remarkable precision. This chapter explores spintronic devices based on heterostructure thin films, including spin valves, magnetic tunnel junctions and other devices. This chapter further discusses the role of interfacial engineering, encapsulation strategies, and microfabrication techniques and concludes the challenges and opportunities for future development.