---
title: "Giant magnetoresistance: relative magnetization changed the resistance"
description: "Why did alternating magnetic layers carry current differently when their magnetizations aligned?"
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last_modified: "2026-10-23"
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Materials · Measurements · Explanation

# Giant magnetoresistance: relative magnetization changed the resistance

Why did alternating magnetic layers carry current differently when their magnetizations aligned?

Sandbox Physics · 2026-10-23

Nobel contribution: 2007-1

1. Build magnetic and spacer layers
2. Change the relative magnetizations
3. Measure electrical resistance
4. Compare parallel and antiparallel states

The original multilayer and trilayer measurements used different temperatures and structures; their resistance changes should not be interchanged.

## Two experiments found a large resistance change

Fert’s group reported giant magnetoresistance in iron/chromium multilayers in 1988. Grünberg’s group found enhanced magnetoresistance in related layered structures, published in 1989. Their independent work connected magnetic configuration with electrical transport.

The often-shown large multilayer signal was measured at low temperature. The room-temperature trilayer result had a smaller amplitude; comparing them requires the sample and temperature labels.

Sources: [1] [2]

## Spin-dependent scattering changes the conducting channels

An electron’s scattering depends on its spin relative to a ferromagnetic layer. Parallel layers can offer one relatively favorable channel through the structure. Antiparallel layers force each channel to encounter a less favorable magnetic layer.

Sources: [1]

## An angle curve is a limited device description

A smooth cosine-like interpolation is useful for a simple spin valve with specified parallel and antiparallel resistances. It does not derive the magnetizations from applied field, include domain reversal, or calculate interface scattering from the atomic structure.

$$
R(\theta)=R_{\parallel}+\frac{R_{\mathrm{AP}}-R_{\parallel}}{2}(1-\cos\theta)
$$

Sources: [1] [2]

## The spin-valve Lab records the angular response

The Lab links a visible layer stack and magnetization arrows to a synthetic resistance scan. It makes relative angle the controlled quantity. The original field sweeps contain additional magnetic coupling and hysteresis physics, which the simple angular model leaves out.

Sources: [1] [3]

Continue with the physics

## Try the related models

### [GMR spin valve](https://sandboxphysics.com/labs/gmr-spin-valve/)

Rotate relative magnetizations and record resistance.

The angular interpolation describes a synthetic device; microscopic scattering and hysteresis require more physics.

## Sources and reading notes

1. [2007 Nobel scientific background: giant magnetoresistance](https://www.nobelprize.org/uploads/2018/06/advanced-physicsprize2007.pdf)

   Contrasts the low-temperature multilayer and room-temperature trilayer experiments and explains spin-dependent scattering.

2. [Fert: Nobel lecture slides on giant magnetoresistance (2007)](https://www.nobelprize.org/uploads/2018/06/fert-slides.pdf)

   Resistance curves with explicit layer thicknesses, temperatures and parallel/antiparallel configurations.

3. [Nobel Prize in Physics 2007: official award](https://www.nobelprize.org/prizes/physics/2007/summary/)

   Official attribution and award year. The observation or theoretical paper may be much earlier.

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