nonlinear inductance vs current

[fonograph]

I was reading article about distortion sources in class D amplifiers for audio and there was one thing mentioned that surprised me.There was written that inductance of simple coil inductor varies with current.Now,I know that alot current will heat the copper wire and higher the temperature,higher the resistance but I am not entirely sure that was the thing that the article meant.

Did that article meant just normal heating and resistance rise,or is there some intrinsic nonlinear inductance change vs current that inductors have? I have never heard or read anything suggesting that there is such thing,so I want to ask you experts to tell me how it is.

[PChi]

If the inductor has a ferrite core the permeability https://en.tdk.eu/download/528882/3226013b0ed82a6a2af3666f537cbf83/pdf-n87.pdf(which determines the inductance along with the core dimensions) varies with flux density which varies with current.

[Benta]

There was written that inductance of simple coil inductor varies with current.

This is only true for inductors with core. Air inductors have no current linearity issues (but a lot more interwinding capacitance).

[Zero999]

A similar thing can happen with some cheaper, high capacitance ceramic capacitors: the capacitance falls at higher voltages.
http://www.murata.com/en-us/support/faqs/products/capacitor/mlcc/char/0005

Another mechanism for distortion is magnetic hysteresis in inductors and dielectric absorption in capacitors.