Title

Optimization of Seed Layer Material and Substrate for Signal Enhancement of Magnetoresistive Sensor

Alternative Title

자기저항 센서의 성능 향상을 위한 시드층 및 기판 최적화

DGIST Authors

Sharma Pranita ; CheolGi Kim ; Chun-Yeol You

Advisor

김철기

Co-Advisor(s)

Chun-Yeol You

Issued Date

2025

Awarded Date

2025-08-01

Type

Thesis

Description

Planar Hall Magnetoresistance (PHMR), Seed Layer Engineering, Heavy Metal/Ferromagnet Bilayers, Inverse Spin Hall Effect (ISHE), Spin Hall Magnetoresistance (SMR)

Table Of Contents

Abstract----------(i)
Table of Contents--------(iii)
List of figures--------(v)
List of tables---------(vii)
Outline of the thesis----------(xi)
1. Introduction -------------1
1.1. Magnetoresistance in thin film
1.1.1. AMR------------4
1.1.2. PHMR--------------6
1.1.3. SMR------------8
1.2. Sensitivity of PHMR sensors--------11
1.3. Role of Interface Engineering in Magnetoresistance--------12
1.3.1. Seed Layer effect----------13
1.3.2. Capping Layer effect---------15
1.4. Spin–Orbit Coupling and Spin Transport in HM/FM Systems---------16
2. Experimental techniques-----------18
2.1. Materials-----------18
2.2. Sample fabrication--------18
2.2.1. Photolithography---------18
2.2.2. DC magnetron sputtering system (deposition rate) -------19
2.2.2.1. Determination of Deposition rate-----------20
2.2.2.2. Sensor deposition------------20
2.2.2.3. Electrode deposition--------------20
2.2.3. Liftoff-------------21
2.3. Sample characterization-----------22
2.3.1. Planar hall effect measurements--------------22
2.3.2. Angle Dependent Magnetoresistance measurement (ADMR)------------- 23
2.3.3. SQUID Magnetometry-----------24
2.3.4. Grazing Incidence X-ray Diffraction (GIXRD) ------25
2.3.5. High Resolution- Transmission Electron Microscopy-------------25
2.3.6. X-Ray Photon Spectroscopy---------26
2.3.7. Ferromagnetic Resonance (FMR) and Inverse Spin Hall Effect (ISHE)
Measurements---------27
2.3.8. X-ray Reflectivity (XRR)----------27
3. Tailoring of sensor output and sensitivity by material and thickness of seed layer---------29
3.1. Seed layer material and thickness effect on Sensor output and sensitivity-----29
3.2. Seed layer material and thickness effect on structural properties of sensing layer----37
3.3. Seed layer material and thickness effect on magnetic properties of sensing layer----42
4. Seed layer material and thickness effect on magnetization dynamics of sensing layer--45
4.1. Seed a layer material and thickness on Ferromagnetic resonance and Gilberts
damping---------45
4.2. Inverse spin hall effect measurements---------53
4.3. Spin hall magnetoresistance and its effect on Total MR measurement----------57
5. Substrate-Dependent Planar Hall Sensor measurements------------65
Conclusion and Perspective----------71
References--------------72
List of Publications---------------80

URI

https://scholar.dgist.ac.kr/handle/20.500.11750/59800
http://dgist.dcollection.net/common/orgView/200000889031

DOI

10.22677/THESIS.200000889031

Degree

Doctor

Department

Department of Physics and Chemistry

Publisher

DGIST

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