Welcome to " BLS & Microwave Magnetism" Lab
The mainly topics of our teams are: Brillouin light scattering, Magnons-Photons interactions, Magnetic anisotropy and spin dynamics in magnetic thin films, and microwave measurement methods for GHz properties of materials. Details as follow:
- Brillouin light scattering
- Magnons-Photons interactions
- Magnetic anisotropy and spin dynamics in magnetic thin films
- Study the quantum chaos with microwaves
- Microwave imaging and near field magnetic microscrope
- Study the quantum communication with photonic crystals
Resume
School of physics science and technology, Lanzhou University - Associate Professor
May, 2014 / Now
School of physics science and technology, Lanzhou University - Assistant Professor
Oct. 2013 / April, 2014
Temeasek Lab, Physics department, National University of Singapore - Research Scientist
Nov. 2012/ Oct. 2013
Temeasek Lab, Physics department, National University of Singapore - Associate Scientist
Feb. 2012 / Nov. 2012
School of physics science and technology, Lanzhou University - PhD on Condensed Matter Physics
Sep. 2006 / June, 2012
School of physics science and technology, Lanzhou University - Bachelor of Physics
Sep. 2002 / June, 2006
Xingtai No. 1 middle school in Hebei - Senior middle school
Sep. 1999 / June, 2002
Grants lists.
National Natural Science Foundation of China, NSFC 
2019.1-2022.12
(No.51871117) (RMB 600,000)
National Natural Science Foundation of China, NSFC
2015.1-2018.12
(No. 51471080) (RMB 820,000)
National Natural Science Foundation of China, NSFC 
2012.1-2014.12
(No. 51107055) (RMB 250,000)
Doctoral graduate student award in the Ministry of Education
2010.7-2011.12
(RMB 30,000)
Tianjin Dongli district government science and technology plan
2011.8-2012.7
(RMB 15,000)
Fundamental Research Funds for the Central Universities 
2014.1-2015.6
(lzujbky-2014-40) (RMB 40,000)
Fundamental Research Funds for the Central Universities
2010.6-2012.5
(lzujbky-2010-219) (RMB 15,000)
The project of cultivating excellent doctoral dissertations of Lanzhou University
2011.1-2012.6
9. Chi Zhang, Yongzhang Shi, Weihua Zhang, Changjun Jiang and Guozhi Chai, Ultra-strong magnon-photon coupling induced in the photonic crystals with an YGaGeIG defect. Applied Physics Letters, 115(2): 022407, 2019.
8. Wenqiang Wang, Pingping Li, Cuimei Cao, Fufu Liu, Rujun Tang, Guozhi Chai and Changjun Jiang, Temperature dependence of interlayer exchange coupling and Gilbert damping in synthetic antiferromagnetic trilayers investigated using broadband ferromagnetic resonance. Applied Physics Letters, 113(2): 042401, 2018.
7. Dongshan Zhang, Wenjie Song and Guozhi Chai, Spin-wave magnon-polaritons in a split-ring resonator/single-crystalline YIG system. J. Phys. D: Appl. Phys. 50, 205003 (2017).
6. Chengyi Li, Guozhi Chai*, Chengcheng Yang, Wenfeng Wang and Desheng Xue. Tunable Zero-Field Ferromagnetic Resonance Frequency from S to X Band in Oblique Deposited CoFeB Thin Films. Scientific Reports, 5: 17023, 2015.
5. Guozhi Chai*, Nguyen N. Phuoc, and C. K. Ong, Angular tunable zero-field ferromagnetic resonance frequency in oblique sputtered CoFeBSm thin films. Applied Physics Express 7(6): 063001-4, 2014.
4. Guozhi Chai*, Nguyen N. Phuoc, and C. K. Ong. High thermal stability of zero-field ferromagnetic resonance above 5 GHz in ferrite-doped CoFe thin films. Applied Physics Letters, 103(4): 042412-5, 2013.
3. Guozhi Chai, Nguyen N. Phuoc, and C. K. Ong*, Exchange coupling driven omnidirectional rotatable anisotropy in ferrite doped CoFe thin film. Scientific Reports. 2: 832-5, 2012.
2. Guozhi Chai, Yuancai Yang, Jingyi Zhu, Min Lin, Wenbo Sui, Dangwei Guo, Xiling Li, and Desheng Xue*. Adjust the resonance frequency of (Co90Nb10/Ta)n multilayers from 1.4 to 6.5 GHz by controlling the thickness of Ta interlayers. Applied Physics Letters, 96(1): 012505-3, 2010.
1. Guozhi Chai, Desheng Xue*, Xiaolong Fan, Xiling Li, and Dangwei Guo. Extending the Snoek’s limit of single layer film in (Co96Zr4/Cu)n multilayers. Applied Physics Letters, 93(15):152516, 2008.
Research works
In-plane Isotropic Microwave Performance of CoZr Trilayer in GHz Range
In this work, we investigate the high frequency performance of Co90Zr10/SiO2/Co90Zr10 trilayers. It
is demonstrated that the in-plane isotropic microwave performance is theoretically derived from
the solution of the Landau-Lifshitz-Gilbert equation and experimentally achieved in that sandwich
structured film. The isotropic microwave performance can be tuned to higher resonance
frequency up to 5.3 GHz by employing the oblique deposition technique.
Tunable zero-field ferromagnetic resonance frequency from S to X band in oblique deposited CoFeB thin films
We performed an investigation of the static and high frequency magnetic
properties for oblique sputtered CoFeB thin films. The static magnetic results revealed that oblique
sputtered CoFeB thin films possess well defined in-plane uniaxial magnetic anisotropy, which
increases monotonically from 50.1 to 608.8 Oe with the increasing of deposition angle from 10° to
70°. Continuous modification of the resonance frequency of CoFeB thin films in a range of
2.83–9.71 GHz (covers three microwave bands including S, C and X bands) has been achieved.
Spin wave magnon-polaritons in a split-ring resonator/single crystalline YIG system
In this work, the spin wave magnon-polaritons are studied by using a split-ring resonator
loaded by a round shape single-crystal bulk yttrium-iron-garnet chip. The
coherent magnon-photon coupling of high index modes spin-wave resonances as well
as ferromagnetic resonance with SRR resonances can be observed. The coupling
strength is mode dependent and it decreases with increasing mode index. These
results may be useful for understanding the strongly hybridized spin wave magnonphoton coupling system.
A designed shorted microstrip probe for detecting the temperature dependence high frequency permeability of magnetic thin films
A temperature dependence characterization system of microwave permeability of magnetic thin film up to 10 GHz in the temperature range from room temperature up to 200 °C is designed and fabricated. It is based on a designed one-port shorted microstrip probe made by microwave printed circuit board (PCB) for detecting the high frequency permeability of magnetic thin films without limitations in sample size. Without contacting the magnetic thin films to the probe, the microwave permeability of the film can be detected with almost as the same accuracy by comparing with the shorted microstrip transmission-line fixture. The complex permeability can be deduced by an analytical approach from the measured reflection coefficient of a strip line (S11) with and without a ferromagnetic film material on it. The procedures are the same with the shorted microstrip transmission-line method. The microwave permeability of an oblique deposited CoZr thin film was investigated with this probe. The room temperature permeability results of the CoZr film agree well with results obtained from the established short-circuited microstrip perturbation method. Temperature dependence permeability results fit well with the Landau–Lifshitz–Gilbert equation. Developments of the temperature dependent measurement of magnetic properties of the magnetic thin film are important to the high frequency applications of magnetic devices at high temperatures.
principle of Brillouin light scattering (BLS)
Publications
Up to 21th May. 2018, I have published 39 papers with 20 as first author or corresponding author. 3 in APL, 2 in APEX, 8 in JAP, 6 in JPD, 4 in Sci. Rep., 3 in JMMM, 5 in J. Alloy. Compd., 8 in other journals. Total citations are 459, with h index as 13 (data from web of science).
Selected Publications
9. Chi Zhang, Yongzhang Shi, Weihua Zhang, Changjun Jiang and Guozhi Chai, Ultra-strong magnon-photon coupling induced in the photonic crystals with an YGaGeIG defect. Applied Physics Letters, 115(2): 022407, 2019.
8. Wenqiang Wang, Pingping Li, Cuimei Cao, Fufu Liu, Rujun Tang, Guozhi Chai and Changjun Jiang, Temperature dependence of interlayer exchange coupling and Gilbert damping in synthetic antiferromagnetic trilayers investigated using broadband ferromagnetic resonance. Applied Physics Letters, 113(2): 042401, 2018.
7. Dongshan Zhang, Wenjie Song and Guozhi Chai, Spin-wave magnon-polaritons in a split-ring resonator/single-crystalline YIG system. J. Phys. D: Appl. Phys. 50, 205003 (2017).
6. Chengyi Li, Guozhi Chai*, Chengcheng Yang, Wenfeng Wang and Desheng Xue. Tunable Zero-Field Ferromagnetic Resonance Frequency from S to X Band in Oblique Deposited CoFeB Thin Films. Scientific Reports, 5: 17023, 2015.
5. Guozhi Chai*, Nguyen N. Phuoc, and C. K. Ong, Angular tunable zero-field ferromagnetic resonance frequency in oblique sputtered CoFeBSm thin films. Applied Physics Express 7(6): 063001-4, 2014.
4. Guozhi Chai*, Nguyen N. Phuoc, and C. K. Ong. High thermal stability of zero-field ferromagnetic resonance above 5 GHz in ferrite-doped CoFe thin films. Applied Physics Letters, 103(4): 042412-5, 2013.
3. Guozhi Chai, Nguyen N. Phuoc, and C. K. Ong*, Exchange coupling driven omnidirectional rotatable anisotropy in ferrite doped CoFe thin film. Scientific Reports. 2: 832-5, 2012.
2. Guozhi Chai, Yuancai Yang, Jingyi Zhu, Min Lin, Wenbo Sui, Dangwei Guo, Xiling Li, and Desheng Xue*. Adjust the resonance frequency of (Co90Nb10/Ta)n multilayers from 1.4 to 6.5 GHz by controlling the thickness of Ta interlayers. Applied Physics Letters, 96(1): 012505-3, 2010.
1. Guozhi Chai, Desheng Xue*, Xiaolong Fan, Xiling Li, and Dangwei Guo. Extending the Snoek’s limit of single layer film in (Co96Zr4/Cu)n multilayers. Applied Physics Letters, 93(15):152516, 2008.
2019
1. Lulu Pan; Wenfeng Wang; Wentao Wang; Peng Zhang; Li Xi; Guozhi Chai; Desheng Xue, Rotatable anisotropy in Fe4N thin film with quasi-single magnetic domain.Journal of Alloys and Compounds.777, 1191-1196 (2019).
2.Cuimei Cao, Lvkang Shen, Shiwei Chen, Kunya Yang, Guohua Lan, Pingping Li, Wenqiang Wang, Ming Liu, Guozhi Chai and Changjun Jiang, Reciprocal-space-resolved piezoelectric control of non-volatile magnetism in epitaxial LiFe5O8 film on Pb(Mg1/3Nb2/3)0.7Ti0.3O3 substrate. Applied Physics Letters, 114: 112402, 2019.
3. Chi Zhang, Yongzhang Shi, Weihua Zhang, Changjun Jiang and Guozhi Chai, Ultra-strong magnon-photon coupling induced in the photonic crystals with an YGaGeIG defect. Applied Physics Letters, 115(2): 022407, 2019.
4. Yongzhang Shi; Dongshan Zhang; Changjun Jiang; Guozhi Chai, Control of photon-magnon coupling with a nonuniform microwave magnetic field. J. Phys. D: Appl. Phys. 52: 305003, 2019.
5. Yangping Wang, Fufu Liu, Cuimei Cao, Cai Zhou, Guozhi Chai, and Changjun Jiang, Ionic-liquid gating controls anomalous hall resistivity of Co/Pt perpendicular magnetic anisotropy films. Journal of Magnetism and Magnetic Materials, 491, 165626, 2019.
2018
1. Huige Ma, Chengyi Li, Wenfeng Wang and Guozhi Chai1, Thickness-dependent resonance frequency of non-uniform procession mode in CoZr stripe-domain magnetic films. J. Phys. D: Appl. Phys. 51, 285004 (2018).
2. Wenqiang Wang, Pingping Li, Cuimei Cao, Fufu Liu, Rujun Tang, Guozhi Chai, and Changjun Jiang, Temperature dependence of interlayer exchange coupling and Gilbert damping in synthetic antiferromagnetic trilayers investigated using broadband ferromagnetic resonance. Applied Physics Letters. 113, 042401 (2018).
3. Cunxu,Gao ; Yu,Miao ;Yutian,Wang ; Guozhi ,Chai,;Peng,Chen, ; Desheng,Xue, Interface-induced spiral magnetic structure of epitaxial Fe films on GaAs(001). Aip Advances. 8, 125026 (2018).
2015
2014
2013
2012
2011
2010
2009
2008
Team members
Open positions
Contact Us
- +86 931 8914160
- http://nano.lzu.edu.cn/chai
- chaigzh@lzu.edu.cn
- 1301#, Ligong Building, Lanzhou University, 222# South Tianshui Road,Lanzhou, Gansu, China, Zip: 730000
