There are mainly two types of magnets: One is Samarium Cobalt magnet and another one is Neodymium magnet. The physical properties for these two types of magnets can be found on http://www.magnetsales.com/SMCO/smcoprops.htm and http://www.magnetsales.com/Neo/Neoprops.htm. Here we list some of them that  are relevant to our investigations.

||<style="text-align: center;"> '''Description''' ||<style="text-align: center;">'''SmCo 1-5 Alloys''' ||<style="text-align: center;"> '''SmCo 2-17 Alloys''' ||<style="text-align: center;"> '''NdFeB''' ||
||<style="text-align: center;"> Young's modulus ||<style="text-align: center;"> 158 GPa ||<style="text-align: center;"> 117 GPa ||<style="text-align: center;"> 166 GPa ||
||<style="text-align: center;"> Density ||<style="text-align: center;">8.2g/cm^3^ ||<style="text-align: center;">8.4g/cm^3^ ||<style="text-align: center;">7.4g/cm^3^ ||
||<style="text-align: center;"> Remanence (Br) ||<style="text-align: center;"> 0.8T to 1.2T ||<style="text-align: center;"> 0.8T to 1.2T ||<style="text-align: center;"> 0.7T to 1.4T ||
||<style="text-align: center;"> Coercivity (Hc) ||<style="text-align: center;"> ~800kA/m ||<style="text-align: center;"> ~800kA/m ||<style="text-align: center;">500kA/m to 1000kA/m ||
||<style="text-align: center;"> Intrinsic Coercivity (Hci) ||<style="text-align: center;">710kA/m to 2000kA/m ||<style="text-align: center;">710kA/m to 2000kA/m ||<style="text-align: center;">710kA/m to 3000kA/m ||
||<style="text-align: center;"> Recoil permeability ||<style="text-align: center;">1.05 ||<style="text-align: center;">1.05 ||<style="text-align: center;">1.05 ||
||<style="text-align: center;"> Curie temperature ||<style="text-align: center;"> 750°C ||<style="text-align: center;"> 825°C ||<style="text-align: center;"> 310°C ||
||<style="text-align: center;"> Temperature coefficient ||<style="text-align: center;"> -0.043%/°C ||<style="text-align: center;"> -0.03%/°C ||<style="text-align: center;"> -0.09 to 0.13%/°C ||
||<style="text-align: center;"> Maximum Operating Temperature ||<style="text-align: center;"> 250°C ||<style="text-align: center;"> 300°C ||<style="text-align: center;"> 150°C ||
||<style="text-align: center;"> Electrical Resistivity ||<style="text-align: center;"> 5µ ohm cm ||<style="text-align: center;"> 86µ ohm cm ||<style="text-align: center;"> 160µ ohm cm ||


To understand what those quantities represent, we can look at the hysteresis curve for a typical magnet as shown in the figure below.

{{attachment:fig_hysteresis_curve.JPG}}

Here {{attachment:fig_Br.JPG}} is the remanence which is the remained magnetization of the permanent magnet when the external fields are removed; {{attachment:fig_coercivity.JPG}} is the coercivity (those who forget its meaning can refer to http://en.wikipedia.org/wiki/Coercivity.); {{attachment:fig_recoil_permeability.JPG}} is the recoil permeability which is the slope for the magnetization and demagnetization as shown in the hysteresis curve; {{attachment:fig_intrinsic_coercivity.JPG}} is the intrinsic coercivity. The difference between coercivity and intrinsic coercivity can refer to http://www.mceproducts.com/knowledge-base/article/article-dtl.asp?id=86.