[20a-B101-1~10] 10.3 Spin devices, magnetic memories and storages

▼ [20a-B101-2] Large linear sensitivity of CoFe based CIP-GMR magnetic sensor using metastable bcc Cu spacer and auxiliary biquadratic coupling through Rh spacer

〇Dolly Taparia¹, Kresna Bondan Fathoni^1,3, Prabhanjan Dilip Kulkarni¹, Srinivasan Ananthakrishnan², Perumal Alagarsamy^1,2, Sakuraba Yuya^1,2, Nakatani Tomoya¹, Sasaki Taisuke¹, Hono Kazuhiro^1,3 (1.Res. Cen. for Mag. and Spint. Matr., Nat. Inst. for Matr. Sc., Tsuku., 305-0047, Japan, 2.Dept. of Phys., Indian Inst. of Tech. Guwahati, Guwahati, 781-039, India., 3.Grad. Sch. of Pure and Appl. Sc., Univ. of Tsuku., Tsuku., 305-8571, Japan)

Keywords:GMR, Linear Magnetoresistance, Magnetic field sensor, Biquadratic Coupling

Large magnetoresistance (MR) with a linear response to the magnetic field is an important feature in MR devices for magnetic sensor applications. Recently, Fathoni et al. [1] reported the largest MR ratio of 40.5% in trilayer current-in-plane (CIP)-GMR films consisting of antiferromagnetically coupled fully epitaxial all bcc CoFe/ Cu/ CoFe trilayer device. This motivated us to fabricate CIP-GMR films consisting of CoFe(3 nm)/ Rh(0.84 nm)/ CoFe(1.5 nm)/ Cu(1.6 nm)/ CoFe(3 nm)/ MgO(2 nm) on single-crystal MgO (001) substrate to realize large linear sensitivity for practical magnetic sensors. Numerical analysis of the M-H loop established that the middle CoFe sensing layer is well controlled by the interlayer exchange coupling (IEC) through the Rh spacer, giving it a linear response while keeping the high MR ratio of the bcc CoFe/Cu/CoFe trilayer. As a result, linear MR response with an MR ratio of 21%, highest sensitivity of 0.047%/mT and a reduced nonlinearity of 0.98%FS in a sensing field range of 220 mT could be achieved [2,3]. The observed results illustrate that CIP-GMR devices with a combination of different magnetic couplings between CoFe layers using Rh and metastable bcc Cu spacers are promising candidates of magnetic sensors for wide dynamic range.