US 12020734

Here's a concise summary of US Patent 12020734:

US Patent: 12020734

• Title: Multilayer exchange spring recording media
• Assignee: Mr Technologies GmbH
• Inventors: Dieter Suess
• Filing Date: 2021-10-04
• Issue Date: 2024-06-25
• Abstract: A multilayer exchange spring recording media consists of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.

Plain-Language Overview of Independent Claims:

The patent contains one independent claim: Claim 1.

• Claim 1: This claim describes a magnetic recording system. It includes a writing head and a disk with a magnetic recording medium. The medium consists of:
  • An essentially non-magnetic substrate.
  • An underlayer.
  • An exchange-coupled magnetic multilayer structure, which itself includes:
    • A hard magnetic storage layer made of a perpendicular anisotropy material with a coercive field (Hs) greater than 0.5 Tesla. This layer is positioned with the underlayer between it and the non-magnetic substrate.
    • A nucleation host, which has a lower coercive field (Hn) than the hard magnetic storage layer (Hn < Hs) when considered without the hard magnetic storage layer. This nucleation host is formed on top of the hard magnetic storage layer (meaning the hard layer is between the nucleation host and the substrate). It is exchange coupled to the hard magnetic storage layer.
    • The nucleation host itself has at least two ferromagnetic layers: a first layer with anisotropy K1, and a second layer (closer to the hard magnetic storage layer) with an increased anisotropy K2 (K2 > K1). These first and second ferromagnetic layers within the nucleation host are connected by an exchange coupling layer.

CAFC 2026 Dockets:

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