Patents by Inventor Simon Liao
Simon Liao has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7089650Abstract: Currently, the shield-to-shield separation of a spin valve head cannot be below about 800 ?, mainly due to sensor-to-lead shorting problems. This problem has now been overcome by a manufacturing method that includes inserting a high permeability, high resistivity, thin film shield on the top or bottom (or both) sides of the spin valve sensor. A permeability greater than about 500 is required together with a resistivity about 5 times greater than that of the free layer and an MrT value for the thin film shield that is 4 times greater than that of the free layer.Type: GrantFiled: December 14, 2004Date of Patent: August 15, 2006Assignee: Headway Technologies, Inc.Inventors: Kochan Ju, Cheng Horng, Youfeng Zheng, Simon Liao, Jei-Wei Chang
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Patent number: 7074456Abstract: Currently, the shield-to-shield separation of a spin valve head cannot be below about 800 ?, mainly due to sensor-to-lead shorting problems. This problem has now been overcome by inserting a high permeability, high resistivity, thin film shield on the top or bottom (or both) sides of the spin valve sensor. A permeability greater than about 500 is required together with a resistivity about 5 times greater than that of the free layer and an MrT value for the thin film shield that is 4 times greater than that of the free layer. Five embodiments of the invention are described.Type: GrantFiled: December 14, 2004Date of Patent: July 11, 2006Assignee: Headway Technologies, Inc.Inventors: Kochan Ju, Cheng Horng, Youfeng Zheng, Simon Liao, Jei-Wei Chang
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Patent number: 7075758Abstract: Increases in the AP1 and AP2 thickness cause the free layer to be off-center in a CPP magnetic read head. This problem has been overcome by inserting supplementary magnetic shields within the spin valve, located as close as possible to the stack. These supplementary shields enable the read gap width to be reduced by about 430 ? and the free layer to shift back towards the center by about 30 ?.Type: GrantFiled: September 8, 2003Date of Patent: July 11, 2006Assignee: Headway Technologies, Inc.Inventors: Kunliang Zhang, Kochan Ju, Min Li, Youfeng Zheng, Simon Liao, Yue Liu
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Publication number: 20060146452Abstract: Improved performance of CIP GMR devices has been achieved by modifying the composition of AP2. Said modification comprises the addition of chromium or vanadium to AP2, while still retaining its ferromagnetic properties. Examples of alloys suitable for use in AP2 include FeCr, NiFeCr, NiCr, CoCr, CoFeCr, and CoFeV. The ruthenium layer normally used to effect antiferromagnetic coupling between AP1 and AP2 is retained.Type: ApplicationFiled: January 4, 2005Publication date: July 6, 2006Inventors: Min Li, Simon Liao, Kunliang Zhang, Rachid Sbiaa
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Patent number: 7068478Abstract: Replacing ruthenium with rhodium as the AFM coupling layer in a synthetically pinned CPP GMR structure enables the AP1/AP2 thicknesses to be increased. This results in improved stability and allows the free layer and AFM layer thicknesses to be decreased, leading to an overall improvement in the device performance. Another key advantage of this structure is that the magnetic annealing requirements (to establish antiparallelism between AP1 and AP2) can be significantly relaxed.Type: GrantFiled: July 31, 2003Date of Patent: June 27, 2006Assignee: Headway Technologies, Inc.Inventors: Min Li, Kunliang Zhang, Rachid Sbiaa, Cheng T. Horng, Simon Liao, Kochan Ju
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Patent number: 7060321Abstract: Currently, the shield-to-shield separation of a spin valve head cannot be below about 800 ?, mainly due to sensor-to-lead shorting problems. This problem has now been overcome by inserting a high permeability, high resistivity, thin film shield on the top or bottom (or both) sides of the spin valve sensor. A permeability greater than about 500 is required together with a resistivity about 5 times greater than that of the free layer and an MrT value for the thin film shield that is 4 times greater than that of the free layer. Five embodiments of the invention are described.Type: GrantFiled: December 14, 2004Date of Patent: June 13, 2006Assignee: Headway Technologies, Inc.Inventors: Kochan Ju, Cheng Horng, Youfeng Zheng, Simon Liao, Jei-Wei Chang
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Publication number: 20060061919Abstract: It has been found that the insertion of a copper laminate within CoFe, or a CoFe/NiFe composite, leads to higher values of CPP GMR and DRA. However, this type of structure exhibits very negative magnetostriction, in the range of high ?10?6 to ?10?5. This problem has been overcome by giving the copper laminates an oxygen exposure treatment When this is done, the free layer is found to have a very low positive magnetostriction constant. Additionally, the value of the magnetostriction constant can be adjusted by varying the thickness of the free layer and/or the position and number of the oxygen treated copper laminates.Type: ApplicationFiled: November 7, 2005Publication date: March 23, 2006Inventors: Min Li, Kunliang Zhang, Masashi Sano, Koichi Terunuma, Simon Liao, Kochan Ju
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Publication number: 20060061918Abstract: A patterned, synthetic, longitudinally exchange biased GMR sensor is provided which has a narrow effective trackwidth and reduced side reading. The advantageous properties of the sensor are obtained by satisfying a novel relationship between the magnetizations (M) of the ferromagnetic free layer (F1) and the ferromagnetic biasing layer (F2) which enables the optimal thicknesses of those layers to be determined for a wide range of ferromagnetic materials and exchange coupling materials. The relationship to be satisfied is MF2/MF1=(Js+Jex)/Js, where Js is the synthetic coupling energy between F1 and F2 and Jex is the exchange energy between F2 and an overlaying antiferromagnetic pinning layer. An alternative embodiment omits the overlaying antiferromagnetic pinning layer which causes the relationship to become MF2/MF1=1.Type: ApplicationFiled: November 1, 2005Publication date: March 23, 2006Inventors: Min Li, You Zheng, Simon Liao, Kochan Ju
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Patent number: 7016168Abstract: A current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) sensor of the synthetic spin valve type is provided, the sensor comprising a GMR stack having a substantially square lateral cross-section, a Cu spacer layer of smaller square cross-section formed centrally on the GMR stack and a capped ferromagnetic free layer of substantially square, but even smaller cross-sectional area, formed centrally on the spacer layer. The stepped, reduced area geometry of the sensor provides a significant improvement in its GMR ratio (DR/R), a reduced resistance, R, and elimination of Joule heating hot-spots in regions of high resistance such as the antiferromagnetic pinning layer and its seed layer.Type: GrantFiled: November 20, 2003Date of Patent: March 21, 2006Assignee: Headway Technologies, Inc.Inventors: Min Li, Kochan Ju, Youfeng Zheng, Simon Liao, Jeiwei Chang
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Patent number: 7010848Abstract: A patterned, synthetic, longitudinally exchange biased GMR sensor is provided which has a narrow effective trackwidth and reduced side reading. The advantageous properties of the sensor are obtained by satisfying a novel relationship between the magnetizations (M) of the ferromagnetic free layer (F1) and the ferromagnetic biasing layer (F2) which enables the optimal thicknesses of those layers to be determined for a wide range of ferromagnetic materials and exchange coupling materials. The relationship to be satisfied is MF2/MF1=(Js+Jex)/Js, where Js is the synthetic coupling energy between F1 and F2 and Jex is the exchange energy between F2 and an overlaying antiferromagnetic pinning layer. An alternative embodiment omits the overlaying antiferromagnetic pinning layer which causes the relationship to become MF2/MF1=1.Type: GrantFiled: February 15, 2002Date of Patent: March 14, 2006Assignee: Headway Technologies, Inc.Inventors: Min Li, You Feng Zheng, Simon Liao, Kochan Ju
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Patent number: 7006337Abstract: Nano-oxide based current-perpendicular-to-plane (CPP) magnetoresistive (MR) sensor stacks are provided, together with methods for forming such stacks. Such stacks have increased resistance and enhanced magnetoresistive properties relative to CPP stacks made entirely of metallic layers. Said enhanced properties are provided by the insertion of magnetic nano-oxide layers between ferromagnetic layers and non-magnetic spacer layers, whereby said nano-oxide layers increase resistance and exhibit spin filtering properties. CPP sensor stacks of various types are provided, all having nano-oxide layers formed therein, including the spin-valve type and the synthetic antiferromagnetic pinned layer spin-valve type. Said stacks can also be formed upon each other to provide laminated stacks of different types.Type: GrantFiled: March 28, 2005Date of Patent: February 28, 2006Assignee: Headway Technologies, Inc.Inventors: Bernard Dieny, Cheng Horng, Kochan Ju, Min Li, Simon Liao
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Patent number: 6999286Abstract: Nano-oxide based current-perpendicular-to-plane (CPP) magnetoresistive (MR) sensor stacks are provided, together with methods for forming such stacks. Such stacks have increased resistance and enhanced magnetoresistive properties relative to CPP stacks made entirely of metallic layers. Said enhanced properties are provided by the insertion of magnetic nano-oxide layers between ferromagnetic layers and non-magnetic spacer layers, whereby said nano-oxide layers increase resistance and exhibit spin filtering properties. CPP sensor stacks of various types are provided, all having nano-oxide layers formed therein, including the spin-valve type and the synthetic antiferromagnetic pinned layer spin-valve type. Said stacks can also be formed upon each other to provide laminated stacks of different types.Type: GrantFiled: March 28, 2005Date of Patent: February 14, 2006Assignee: Headway Technologies, Inc.Inventors: Bernard Dieny, Cheng T. Horng, Kochan Ju, Min Li, Simon Liao
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Patent number: 6998150Abstract: It has been found that the insertion of a copper laminate within CoFe, or a CoFe/NiFe composite, leads to higher values of CPP GMR and DRA. However, this type of structure exhibits very negative magnetostriction, in the range of high ?10?6 to ?10?5. This problem has been overcome by giving the copper laminates an oxygen exposure treatment When this is done, the free layer is found to have a very low positive magnetostriction constant. Additionally, the value of the magnetostriction constant can be adjusted by varying the thickness of the free layer and/or the position and number of the oxygen treated copper laminates.Type: GrantFiled: March 12, 2003Date of Patent: February 14, 2006Assignee: Headway Technologies, Inc.Inventors: Min Li, Kunliang Zhang, Masashi Sano, Koichi Terunuma, Simon Liao, Kochan Ju
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Patent number: 6995959Abstract: Currently, the shield-to-shield separation of a spin valve head cannot be below about 800 ?, mainly due to sensor-to-lead shorting problems. This problem has now been overcome by inserting a high permeability, high resistivity, thin film shield on the top or bottom (or both) sides of the spin valve sensor. A permeability greater than about 500 is required together with a resistivity about 5 times greater than that of the free layer and an MrT value for the thin film shield that is 4 times greater than that of the free layer. Five embodiments of the invention are described.Type: GrantFiled: December 14, 2004Date of Patent: February 7, 2006Assignee: Headway Technologies, Inc.Inventors: Kochan Ju, Cheng Horng, Youfeng Zheng, Simon Liao, Jei-Wei Chang
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Patent number: 6987651Abstract: Nano-oxide based current-perpendicular-to-plane (CPP) magnetoresistive (MR) sensor stacks are provided, together with methods for forming such stacks. Such stacks have increased resistance and enhanced magnetoresistive properties relative to CPP stacks made entirely of metallic layers. Said enhanced properties are provided by the insertion of magnetic nano-oxide layers between ferromagnetic layers and non-magnetic spacer layers, whereby said nano-oxide layers increase resistance and exhibit spin filtering properties. CPP sensor stacks of various types are provided, all having nano-oxide layers formed therein, including the spin-valve type and the synthetic antiferromagnetic pinned layer spin-valve type. Said stacks can also be formed upon each other to provide laminated stacks of different types.Type: GrantFiled: March 28, 2005Date of Patent: January 17, 2006Assignee: Headway Technologies, Inc.Inventors: Bernard Dieny, Cheng Horng, Kochan Ju, Min Li, Simon Liao
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Publication number: 20060007608Abstract: Reduction of the free layer thickness in GMR devices is desirable in order to meet higher signal requirements, besides improving the GMR ratio itself. However, thinning of the free layer reduces the GMR ratio and leads to poor thermal stability. This problem has been overcome by making AP2 from an inverse GMR material and by changing the free layer from a single uniform layer to a ferromagnetic layer AFM (antiferromagnetically) coupled to a layer of inverse GMR material. Examples of alloys that may be used for the inverse GMR materials include FeCr, NiFeCr, NiCr, CoCr, CoFeCr, and CoFeV. Additionally, the ruthenium layer normally used to effect antiferromagnetic coupling can be replaced by a layer of chromium. A process to manufacture the structure is also described.Type: ApplicationFiled: September 16, 2005Publication date: January 12, 2006Inventors: Min Li, Simon Liao, Kochan Ju
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Patent number: 6985337Abstract: Nano-oxide based current-perpendicular-to-plane (CPP) magnetoresistive (MR) sensor stacks are provided, together with methods for forming such stacks. Such stacks have increased resistance and enhanced magnetoresistive properties relative to CPP stacks made entirely of metallic layers. Said enhanced properties are provided by the insertion of magnetic nano-oxide layers between ferromagnetic layers and non-magnetic spacer layers, whereby said nano-oxide layers increase resistance and exhibit spin filtering properties. CPP sensor stacks of various types are provided, all having nano-oxide layers formed therein, including the spin-valve type and the synthetic antiferromagnetic pinned layer spin-valve type. Said stacks can also be formed upon each other to provide laminated stacks of different types.Type: GrantFiled: March 28, 2005Date of Patent: January 10, 2006Assignee: Headway Technologies, Inc.Inventors: Bernard Dieny, Cheng Horng, Kochan Ju, Min Li, Simon Liao
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Patent number: 6972934Abstract: A method for forming top and bottom spin valve sensors and the sensors so formed, the sensors having a strongly coupled SyAP pinned layer and an ultra-thin antiferromagnetic pinning layer. The two strongly coupled ferromagnetic layers comprising the SyAP pinned layer in the top valve configuration are separated by a Ru spacer layer approximately 3 angstroms thick, while the two layers in the bottom spin valve configuration are separated by a Rh spacer layer approximately 5 angstroms thick. This allows the use of an ultra thin MnPt antiferromagnetic pinning layer of thickness between approximately 80 and approximately 150 angstroms. The sensor structure produced thereby is suitable for high density applications.Type: GrantFiled: July 2, 2004Date of Patent: December 6, 2005Assignee: Headway Technologies, Inc.Inventors: Cheng T. Horng, Kochan Ju, Mao-Min Chen, Min Li, Ru-Ying Tong, Simon Liao
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Publication number: 20050248888Abstract: Nano-oxide based current-perpendicular-to-plane (CPP) magnetoresistive (MR) sensor stacks are provided, together with methods for forming such stacks. Such stacks have increased resistance and enhanced magnetoresistive properties relative to CPP stacks made entirely of metallic layers. Said enhanced properties are provided by the insertion of magnetic nano-oxide layers between ferromagnetic layers and non-magnetic spacer layers, whereby said nano-oxide layers increase resistance and exhibit spin filtering properties. CPP sensor stacks of various types are provided, all having nano-oxide layers formed therein, including the spin-valve type and the synthetic antiferromagnetic pinned layer spin-valve type. Said stacks can also be formed upon each other to provide laminated stacks of different types.Type: ApplicationFiled: March 28, 2005Publication date: November 10, 2005Inventors: Bernard Dieny, Cheng Horng, Kochan Ju, Min Li, Simon Liao
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Patent number: 6953601Abstract: Reduction of the free layer thickness in GMR devices is desirable in order to meet higher signal requirements, besides improving the GMR ratio itself. However, thinning of the free layer reduces the GMR ratio and leads to poor thermal stability. This problem has been overcome by making AP2 from an inverse GMR material and by changing the free layer from a single uniform layer to a ferromagnetic layer AFM (antiferromagnetically) coupled to a layer of inverse GMR material. Examples of alloys that may be used for the inverse GMR materials include FeCr, NiFeCr, NiCr, CoCr, CoFeCr, and CoFeV. Additionally, the ruthenium layer normally used to effect antiferromagnetic coupling can be replaced by a layer of chromium. A process to manufacture the structure is also described.Type: GrantFiled: June 11, 2002Date of Patent: October 11, 2005Assignee: Headway Technologies, Inc.Inventors: Min Li, Simon Liao, Kochan Ju