Spin Valve

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This invention describes an improved spin valve structure for MRAM (Magnetoresistive Random Access Memory) memory. The spin valve features two magnetic layers with perpendicular magnetization, separated by a non-magnetic intermediate layer. The reference layer is made from a ferrimagnetic material, while the free layer is made from a ferro- or ferrimagnetic material. This design introduces a stable exchange bias between the two layers, leading to enhanced data stability, the ability to reset and rewrite memory at room temperature, and eliminates the need for complex initialization processes. The invention also prevents decay of the stored information over time and avoids performance degradation due to repeated use, known as the training effect.

Use CasesContent extracted from patent full text and abstract with AI.

• Non-volatile memory devices, specifically MRAM modules for computers and servers.
• Embedded memory in mobile devices requiring fast, high-density, and stable data storage.
• Applications in automotive, aerospace, or industrial systems where robust and reliable memory is vital.
• Secure hardware, such as cryptographic storage and tamper-evident digital systems.
• Data logging devices that require data retention without continuous power.
• Wearable and IoT (Internet of Things) devices needing low-power, high-endurance memory.

BenefitsContent extracted from patent full text and abstract with AI.

• Improved data retention and time stability at room temperature, with selectable stability duration from days to years depending on material choice.
• Enables full resetting (rewriting) of the entire memory unit without needing high temperatures or complex external magnetic field procedures (no Field Cooling/Growing needed).
• Eliminates the training effect, providing consistent, reliable memory behavior over repeated rewrite cycles.
• Supports high-density data storage: spin valve elements can be as small as 30 x 30 nm, allowing for highly compact memory arrays.
• Low-energy operation due to lower switching fields, reducing power consumption for writing/erasing.
• Simple fabrication using directly exchange-coupled ferrimagnetic and ferromagnetic materials, reducing manufacturing complexity.

Technical Classifications (CPCs)

Inventors & Applicants

Patent Abstract

The invention relates to a spin valve for use in MRAM memory units, said spin valve consisting of two layers which are magnetized perpendicularly to the layer plane and which are separated by an intermediate layer. The reference layer is made of a ferrimagnetic material, and the free layer is made of a ferro- or ferrimagnetic material. An exchange bias occurs in the spin valve between the reference layer and the free layer, said exchange bias stabilizing the preferred orientation of the free layer. The spin valve can be read and completely rewritten (reset) at room temperature. Additionally, the exchange bias of the spin valve does not exhibit a training effect. The time stability of stored information is specified dependent on the set coercivity of the reference layer.