# US 2013/0152380 A1 · Apparatus and method for reducing inductor saturation in magnetic fields > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0152380 A1 - Document ID: US20130152380A1 - Status: Published application - Kind: A1 - Application number: 13/769,443 - Filed: 2013-02-18 - Published: 2013-06-20 - Earliest claimed: 2010-01-05 - Assignees: Cardiac Pacemakers, Inc. - Inventors: Jeffrey E. Stahmann; Scott R. Stubbs; Arthur Foster - Web page: https://patentgrep.com/patent/US20130152380A1 ## CPC - H01F 41/00: Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties - H01F 3/02: made from sheets - H01F 27/245: made from sheets, e.g. grain-oriented (H01F27/26 takes precedence) - H01F 1/344: {Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4} - H01F 2003/106: {Magnetic circuits using combinations of different magnetic materials} - Y10T 29/4902: Electromagnet, transformer or inductor - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract This document discusses, among other things, an inductive component that can include a core having two portions: (1) a first portion composed of a first material having a first magnetic saturation level; and (2) a second portion composed of a second material selected to provide inductance for the inductive component when an external magnetic field is greater than the first magnetic saturation level. In an example, the first portion can be composed of a material having a relatively low magnetic saturation level (e.g., a ferrite), and the second portion can be composed of a material having a relatively high magnetic saturation level (e.g., a high permeability iron alloy). ## Claims ### Claim 1 A method comprising: providing a first material and a second material; generating a first inductance, with the first material, from a first current propagating through at least one loop of conductive wire, when the first material is exposed to an external magnetic field below a first magnetic saturation level of the first material; and generating a second inductance, with the second material, from a second current propagating through the at least one loop of conductive wire, when the second material is exposed to an external magnetic field above the first magnetic saturation level, wherein the second inductance is provided to an inductive component such that the inductive component is configured for operation of an implantable medical device within a magnetic resonance imaging device at exposure to greater than the first magnetic saturation level. ### Claim 2 (depends on 1) The method of claim 1, wherein the first magnetic saturation level is approximately 0.6 Tesla. ### Claim 3 (depends on 1) The method of claim 1, wherein the second inductance is a value that is at least 10 percent of a value of the first inductance when the external magnetic field is above the first magnetic saturation level. ### Claim 4 (depends on 1) The method of claim 1, wherein the first and second inductance are generated via at least one of ferromagnetism and ferrimagnetism. ### Claim 5 (depends on 1) The method of claim 1, wherein the first inductance has a maximum inductance, and wherein the second inductance is a value that is at least 10% of a value of the maximum inductance when the first material substantially saturates. ### Claim 6 (depends on 1) The method of claim 1, wherein the first magnetic saturation level is less than 0.6 Tesla, and wherein the second material has a second magnetic saturation level of greater than 1.5 Tesla. ### Claim 7 (depends on 6) The method of claim 6, wherein the first material includes a ferrite and the second material includes at least one of: a ferromagnetic metallic alloy and a magnetic nanoparticle based material. ### Claim 8 (depends on 1) The method of claim 1, wherein the second material has a volume that is in the range of 5%-30% relative to a volume of the first material. ### Claim 9 (depends on 1) The method of claim 1, wherein a resistivity of the second material is greater than 10 μΩ·cm. ### Claim 10 (depends on 1) The method of claim 1, further comprising: providing a first continuous magnetic loop via the first material; and providing a second continuous magnetic loop via the second material. ### Claim 11 (depends on 1) The method of claim 1, wherein the second material comprises a plurality of sheets interspersed with the first material. ### Claim 12 (depends on 1) The method of claim 1, wherein the first material comprises a plurality of sheets, wherein an insulator is positioned between adjacent pairs of the sheets. ### Claim 13 (depends on 1) The method of claim 1, wherein the second material provides inductance for the inductive component when an external magnetic field is below the first magnetic saturation level. ### Claim 14 (depends on 1) The method of claim 1, further comprising: providing a gap between the first material and the second material. ### Claim 15 (depends on 14) The method of claim 14, wherein the gap is an air gap. ### Claim 16 (depends on 1) The method of claim 1, further comprising: providing a paramagnetic material between the first material and the second material. ### Claim 17 (depends on 1) The method of claim 1, further comprising: providing a diamagnetic material between the first material and the second material. ### Claim 18 A method comprising: providing a first material and a second material; providing a first electrically conductive wire forming a first at least one loop; positioning a first portion comprising a first material at least partially within the first at least one loop so as to provide a first inductance for the first electrically conductive wire when a current is propagated through the conductive wire, wherein the first material has a first magnetic saturation level; and positioning a second portion comprising a different second material at least partially within the first at least one loop so as to provide a second inductance for the first electrically conductive wire when a current is propagated through the conductive wire, wherein the second material is selected to provide an inductance when an external magnetic field is greater than the first magnetic saturation level, wherein the second inductance is provided to an inductive component such that the inductive component is configured for operation of an implantable medical device within a magnetic resonance imaging device at exposure to greater than the first magnetic saturation level. ### Claim 19 (depends on 18) The method of claim 18, wherein the second material has a higher magnetic saturation level than the first material. ### Claim 20 (depends on 19) The method of claim 19, wherein at least one of the first material and the second material is configured to provide an inductance via at least one of ferromagnetism or ferrimagnetism.