MicroSD cards

my guess would be either a software limitation or the type of formatting used on the sdcards.

32gb is more than enough space for most users

The majority of smartphones only support Micro SD cards up to 32 GB because This is enough memory of any phones and would be either a software limitation, song limitation, picture limitation, application limitation or the type of formatting used on the SD cards.

hi there bud memory card capacity is depend on price of the phone s3 is also a smart phone but it support up to 64 gb.

The SDHC specification is only up to 32GB. The memory addressing capacity of the controller (physically or firmware) is the limitation. If the phone can support SDXC (via native hardware support or firmware update of a SDHC controller capable of handling space addressing requirement of HDXC specification), then it will support more than 32GB.