Strain decoupled sensor

A sensor comprising a substrate and a sensor element anchored to the substrate,

• the substrate and sensor element being of dissimilar materials and having different coefficients of thermal expansion,
• the sensor element and substrate each having a generally planar face arranged substantially parallel to one another,
• the sensor further comprising a single spacer defined by a projection upstanding from a surrounding part of the substrate and whereby the sensor element is anchored upon the substrate,
• wherein the spacer comprises a vertical side,
• the spacer being located so as to space at least part of the sensor element from at least part of the substrate,
• wherein the face of the spacer comprises a smaller area than the face of the substrate and the sensor element, the smaller area comprising less than half of the area of the face of the substrate and less than half of the area of the face of the sensor element,
• wherein the sensor element comprises a magnet assembly comprising:
• a lower pole piece;
• an upper pole piece;
• and
• a magnet located therebetween and comprising a vertical side,
• wherein the vertical side of the magnet is aligned with the vertical side of the spacer, and
• the lower pole piece extends beyond the vertical side of the spacer and the vertical side of the magnet and over a cavity formed in the face of the substrate
• wherein the lower pole piece is directly anchored to the spacer.